# The Panama Canal

> Four centuries of dreams, a French disaster, a new country and a US Canal Zone: how the Panama Canal was built, how its locks lift ships with nothing but gravity, and how it became Panama's. Operate a lock yourself.

Interactive film: https://www.planetpast.com/stories/panama-canal/  
Publisher: PlanetPast (https://www.planetpast.com/) · Published 2026-10-12 · History, Technology

## Prologue

### The narrow land between two oceans
*9 October 2026 · Magnitude 7.7*

A strong earthquake shook Panama. The world’s first question was about a waterway.

On the ninth of October 2026, a magnitude seven point seven earthquake struck Panama, about two hundred kilometres from the capital. Homes were damaged and power failed in several provinces. Within hours, the Panama Canal Authority said ships were still moving, while engineers inspected its structures. Why does a canal matter so much? Because it crosses the narrowest land between two oceans, and because building it took four hundred years of dreams, two attempts, a new country and tens of thousands of lives.

Prologue · Why the news matters

#### The narrow land between two oceans

On 9 October 2026 the US Geological Survey recorded a magnitude 7.7 earthquake in Panama, centred about 12 km west-southwest of Pitaloza Arriba in Herrera province. Buildings were damaged, power went out in several provinces and more than 45 aftershocks followed. The Panama Canal Authority said operations were continuing normally while technical teams inspected its facilities.

- **Magnitude (USGS)**: 7.7 17:56 UTC, depth about 13 km

- **Distance to the capital**: ~200 km epicentre in a thinly populated area

- **The canal**: About 80 km from the Atlantic to the Pacific 13,000–14,000 ships a year, according to the Panama Canal Authority

This story is about the canal itself: why it was so hard to build, who built it, how its locks lift ships over the hills, and how it came to belong to Panama.

How to use: pick a chapter below the scene or press ← → to change step · ▶ plays the step · drag to rotate, scroll or pinch to zoom · “Play the film” runs every step full-screen. Several steps have buttons on the scene that you can operate yourself.

Sources: [USGS: M 7.7, 12 km WSW of Pitaloza Arriba, Panama (9 Oct 2026)](https://earthquake.usgs.gov/earthquakes/eventpage/us6000u18k/executive); [Associated Press: Two powerful earthquakes rock Panama (9 Oct 2026)](https://www.inquirer.com/news/nation-world/panama-two-earthquakes-aftershocks-canal-20261009.html); [Panama Canal Authority: History of the Panama Canal](https://pancanal.com/en/history-of-the-panama-canal/)

## Chapter I · The narrow land

### “The South Sea”
*25 September 1513*

From a ridge in the jungle, a Spanish expedition saw an ocean that Europeans had not known was there.

In September 1513 the Spanish explorer Vasco Núñez de Balboa led an expedition across the isthmus with the help of local guides. On the twenty-fifth he climbed a ridge and saw what he called the South Sea: the Pacific Ocean. Only a narrow strip of land separated two oceans. In 1534 King Charles the Fifth ordered a survey for a route across it. For three centuries, though, goods crossed on mule trails and river boats. The mountains and the jungle were too much.

Chapter I · Step 1 · 1513–1534

#### A sea on the other side

Vasco Núñez de Balboa’s expedition of 1513 made him the first European to see the Pacific from the Americas, on 25 September. The Isthmus of Panama is the narrowest land between the Atlantic and the Pacific, so the idea of a cut through it followed quickly. In 1534 Charles V, Holy Roman Emperor and King of Spain, ordered a survey for a route that would ease voyages between Spain and Peru.

- **First sight of the Pacific**: 1513 Balboa called it the “South Sea”

- **First survey ordered**: 1534 by Charles V

- **Crossing for 300 years**: Mule trails and river boats the Spanish *Camino Real* and Las Cruces trail, plus canoes on the Chagres River; four to eight days by the 1840s

The 3D map uses real elevation data, with heights exaggerated eight times. Here it shows the land before the canal: the Chagres River valley is still dry ground where Gatun Lake lies today.

Sources: [Wikipedia: Vasco Núñez de Balboa](https://en.wikipedia.org/wiki/Vasco_N%C3%BA%C3%B1ez_de_Balboa); [Wikipedia: History of the Panama Canal](https://en.wikipedia.org/wiki/History_of_the_Panama_Canal); [Wikipedia: Panama Canal Railway](https://en.wikipedia.org/wiki/Panama_Canal_Railway); [Terrain Tiles (AWS Open Data; SRTM-based elevation)](https://registry.opendata.aws/terrain-tiles/)

### Gold fever
*1850–1855 · The Panama Railroad*

The California Gold Rush turned a jungle crossing into one of the busiest routes in the world.

In 1848 gold was found in California. There was no railway across the United States, so thousands chose a shortcut: sail to Panama, cross the isthmus, and sail on. An American company began a railroad in 1850. Workers came from the Caribbean, Ireland, India, China and beyond, and laid track through swamp and rainforest. It opened in January 1855: about seventy-seven kilometres from coast to coast, at six times its expected cost. Disease killed thousands of the men who built it. Estimates range from about five thousand to twelve thousand.

Chapter I · Step 2 · 1850–1855

#### The first line across

The 1849 California Gold Rush created a flood of travellers between the US east and west coasts. The first railroad across North America would not be completed until 1869, so the Panama route was the quickest. The Panama Railroad, begun in 1850, ran its first train over the full length on 28 January 1855.

- **Length**: ~77 km 47.6 miles, Colón to Panama City

- **Cost**: US$8 million about six times the original estimate

- **Lives lost**: Estimated 5,000 to 12,000 workers Sources disagree; cholera, malaria and yellow fever were the main killers. Exact records do not exist.

The dashed line on the map is an approximation. Much of the original track ran through the Chagres valley, which was later flooded by Gatun Lake, and the railway was rebuilt on a new route.

Sources: [Wikipedia: Panama Canal Railway](https://en.wikipedia.org/wiki/Panama_Canal_Railway); [Wikipedia: History of the Panama Canal](https://en.wikipedia.org/wiki/History_of_the_Panama_Canal)

## Chapter II · The French dream

### A canal at sea level
*1 January 1881 · The French begin*

The man who built the Suez Canal promised to do it again, without a single lock.

Ferdinand de Lesseps had opened the Suez Canal in 1869: a cut at sea level through flat desert. In 1879 an international congress in Paris voted for a sea-level canal across Panama. Work began on the first of January 1881. But Panama is not a desert. The plan meant digging through the continental divide, about one hundred and ten metres high, and taming the Chagres River, which in the rainy season could rise ten metres. Watch the red: all of it would have to be dug out.

Chapter II · Step 3 · 1879–1881

#### The sea-level plan

Ferdinand de Lesseps, builder of the Suez Canal, insisted on a canal at sea level, like Suez. A congress in Paris in 1879 approved it by 74 votes to 8; among the “no” votes was the engineer Gustave Eiffel. The company obtained a concession from Colombia, which then governed Panama, and digging began in 1881, with work at Culebra from 22 January.

- The continental divide at Culebra originally rose to about 110 m above sea level.

- A sea-level canal must cut below sea level along its whole length.

- The Chagres River crosses the route and could rise about 10 m in the rainy season. A planned dam at Gamboa to control it proved impractical.

The scene is a schematic profile along the route, from the Atlantic (left) to the Pacific (right). Heights are exaggerated about 90 times so they can be seen. The ground line is schematic, drawn through the heights given in the sources; canal depths are illustrative.

Sources: [Wikipedia: History of the Panama Canal](https://en.wikipedia.org/wiki/History_of_the_Panama_Canal); [Wikipedia: Panama Canal](https://en.wikipedia.org/wiki/Panama_Canal)

### Fever and failure
*1881–1889*

Landslides, floods and disease overwhelmed the French effort. Then the money ran out.

The cut at Culebra kept sliding back in. In the rains, the Chagres flooded the works. Worse were yellow fever and malaria. No one yet knew that mosquitoes spread them. By 1884 more than two hundred workers were dying every month. In 1887 de Lesseps finally accepted locks. It was too late. In 1889 the company collapsed, and the savings of eight hundred thousand investors were lost. About twenty-two thousand people had died. A bribery scandal in Paris followed. The summit had been lowered from about a hundred and ten metres to fifty-nine.

Chapter II · Step 4 · 1881–1889

#### Collapse

The French company faced landslides, a river that flooded every rainy season, and disease. Engineers did not yet know that mosquitoes carry yellow fever and malaria. Several of the company’s chief engineers resigned or died. In October 1887 de Lesseps finally accepted a lock canal designed by Jules Dingler and Gustave Eiffel, but in 1889 the company went bankrupt and work stopped on 15 May. The canal was about two-fifths finished.

- **Spent**: ~US$287 million by 1889

- **Investors ruined**: ~800,000 mostly French savers

- **Deaths 1881–1889**: Estimated about 22,000 including as many as 5,000 French citizens; most workers were from the Caribbean. This is an estimate; records were incomplete.

The “Panama scandal” broke in 1892: members of the French government had taken bribes to hide the company’s troubles. A new French company was formed in 1894 to keep the concession and its equipment until a buyer could be found.

In the profile, dark brown shows rock the French removed at the summit; red is what remained for a sea-level canal.

Sources: [Wikipedia: History of the Panama Canal](https://en.wikipedia.org/wiki/History_of_the_Panama_Canal); [Wikipedia: Panama scandals](https://en.wikipedia.org/wiki/Panama_scandals)

## Chapter III · A new country

### A new country, and a zone
*November 1903*

Panama separated from Colombia. Two weeks later, a treaty gave the United States a strip of land across it.

The United States wanted the canal. In 1903 it signed a treaty with Colombia, but Colombia’s Senate rejected it. On the third of November 1903, Panama declared its separation from Colombia. A US warship stood off Colón, and the United States quickly recognised the new republic. On the eighteenth, a treaty was signed in Washington by the Secretary of State and Philippe Bunau-Varilla, a French engineer acting for Panama. It granted the United States, in perpetuity, a zone sixteen kilometres wide across the isthmus. Many Panamanians would resent its terms for decades.

Chapter III · Step 5 · 1903

#### Separation and the Canal Zone

The US Congress had authorised buying the French company’s rights for US$40 million. Colombia’s Senate rejected the Hay–Herrán Treaty on 12 August 1903. On 3 November Panama declared independence; the warship USS *Nashville* was already at Colón, and US forces prevented Colombia from retaking the territory. The US recognised Panama on 13 November.

- **Treaty signed**: 18 Nov 1903 Hay–Bunau-Varilla Treaty

- **Zone width**: 10 miles about 16 km, 5 miles each side of the canal line

- **Payment to Panama**: $10 million plus $250,000 a year

- **Zone area**: ~1,432 km² Panama City and Colón were outside it

The treaty gave the United States the zone “in perpetuity”, with powers to govern it. Panama’s negotiator, Bunau-Varilla, was a French citizen who had not been in Panama for seventeen years and had a financial stake in the old French company. Colombia recognised Panama only in 1909. Supporters in the United States saw a bargain that made the canal possible; many in Panama came to see a treaty imposed on them. Both views shaped the next 96 years.

Gold shading on the map: the approximate Canal Zone, drawn 5 miles either side of today’s canal centre line.

Sources: [Wikipedia: Separation of Panama from Colombia](https://en.wikipedia.org/wiki/Separation_of_Panama_from_Colombia); [Wikipedia: Hay–Bunau-Varilla Treaty](https://en.wikipedia.org/wiki/Hay%E2%80%93Bunau-Varilla_Treaty); [Wikisource: text of the 1903 treaty (Article II)](https://en.wikisource.org/wiki/Hay%E2%80%93Bunau-Varilla_Treaty); [Wikipedia: Panama Canal Zone](https://en.wikipedia.org/wiki/Panama_Canal_Zone); [Wikipedia: History of the Panama Canal](https://en.wikipedia.org/wiki/History_of_the_Panama_Canal)

## Chapter IV · Building it

### Before the digging, the fevers
*1904–1906 · The mosquito war*

The Americans’ first great victory in Panama was not over rock, but over insects.

The United States took over the French works on the fourth of May 1904. Its chief medical officer was William Gorgas. In Cuba, Carlos Finlay and Walter Reed had shown that one mosquito, Aedes aegypti, spreads yellow fever. Ronald Ross had linked malaria to Anopheles mosquitoes. Gorgas’s teams drained and oiled standing water, screened windows, fumigated houses and built piped water so families no longer kept open barrels. Many officials called it a waste of money. President Roosevelt backed Gorgas. By 1906 only one case of yellow fever was reported.

Chapter IV · Step 6 · 1904–1906

#### Defeating yellow fever

Colonel William C. Gorgas had already helped end yellow fever in Havana. His method rested on the work of the Cuban physician Carlos Finlay and the American pathologist Walter Reed, who showed that the *Aedes aegypti* mosquito carries the disease, and on Ronald Ross’s work linking malaria to *Anopheles* mosquitoes.

- Remove breeding water: drain ponds and ditches; spray oil and larvicide on the rest.

- Keep mosquitoes away from people: screens on windows and verandas, nets, quarantine of patients.

- Fumigate buildings, and build piped water systems to replace water barrels in homes.

- **Yellow fever**: 1 case reported in 1906; none in later years of construction

- **Malaria**: Reduced, not ended it remained a major cause of illness

The commission chairman, Theodore Shonts, asked President Theodore Roosevelt to remove Gorgas. After consulting doctors, Roosevelt gave Gorgas his full support.

The red haze on the map is an illustration of mosquito numbers falling, not measured data.

Sources: [Wikipedia: Health measures during the construction of the Panama Canal](https://en.wikipedia.org/wiki/Health_measures_during_the_construction_of_the_Panama_Canal); [Wikipedia: History of the Panama Canal](https://en.wikipedia.org/wiki/History_of_the_Panama_Canal)

### Lift the ships instead
*1906 · John Stevens*

Rather than dig down to the sea, build a lake in the sky and climb up to it.

In 1905 a railway engineer, John Stevens, took charge. He rebuilt the railroad and housing, and began recruiting workers by the thousands. An expert panel voted eight to five for a sea-level canal. Stevens, who had seen the Chagres in flood, called that “an entirely untenable proposition”. His alternative: dam the Chagres at Gatun to make a lake twenty-six metres above the sea. Locks at each end lift ships up to it and lower them down again. The river becomes the canal’s water supply instead of its enemy, and far less rock must be dug. Congress agreed in 1906. Try both plans with the buttons.

Chapter IV · Step 7 · 1905–1906

#### The lock-and-lake design

The first American chief engineer, John Findley Wallace, resigned in 1905. His successor, John F. Stevens, argued for a canal whose locks raise ships to a large artificial lake about 26 m (85 ft) above sea level. Water to work the locks would flow down from the lake by gravity. Roosevelt and Congress accepted the plan in 1906.

**Sea-level** dig the whole route below the sea; the Chagres must be diverted **Lock-and-lake** dam the Chagres; locks lift ships about 26 m; the cut stops 12 m above sea level **Trade-off** locks limit ship size and need water from rain
Use the buttons on the scene to switch between the two plans. Red shows rock to excavate; blue is water.

Sources: [Wikipedia: History of the Panama Canal](https://en.wikipedia.org/wiki/History_of_the_Panama_Canal); [Wikipedia: Culebra Cut](https://en.wikipedia.org/wiki/Culebra_Cut); [Wikipedia: Panama Canal](https://en.wikipedia.org/wiki/Panama_Canal)

### Moving mountains
*1907–1913 · George Goethals*

Steam shovels, dynamite and 160 trains a day carved a canyon through the hills, while a dam turned a valley into a lake.

In 1907 an army engineer, George Goethals, took over. The hardest job was the Culebra Cut: about thirteen kilometres through the continental divide. Around six thousand men drilled and blasted. Steam shovels loaded up to a hundred and sixty trains of rock a day. Landslides buried the work again and again. At Gatun, an earth dam two point three kilometres long blocked the Chagres. In June 1913 its spillway gates closed, and the valley began to fill. Gatun Lake became the largest artificial lake in the world at the time. In October 1913 the last barrier in the cut was blown up, and water joined the two halves.

Chapter IV · Step 8 · 1907–1913

#### The Culebra Cut and Gatun Lake

Goethals divided the work into three divisions. The Central Division under Major David Gaillard dug the Culebra Cut (called the Gaillard Cut from 1915 to 2000) down to 12 m above sea level. Unstable shale caused repeated slides; the first big one, at Cucaracha in 1907, moved about 380,000 m³. On 26 May 1913 steam shovels met at the bottom of the cut.

- **Dynamite in the cut**: ~27,000 t with up to 160 spoil trains a day

- **Gatun Dam**: 2.3 km long 640 m thick at the base; earth fill

- **Lake begins filling**: 27 Jun 1913 spillway gates closed

- **Gamboa dike blown**: 10 Oct 1913 by telegraph signal from Washington

- **Excavated in the American era**: About 183 million m³ about 205 million m³ including the French work

On the map, watch the lake rise from the old river valley to about 26 m. The orange line marks the Culebra Cut. The valley floor under the lake is reconstructed approximately.

Sources: [Wikipedia: History of the Panama Canal](https://en.wikipedia.org/wiki/History_of_the_Panama_Canal); [Wikipedia: Culebra Cut](https://en.wikipedia.org/wiki/Culebra_Cut); [Wikipedia: Gatun Lake](https://en.wikipedia.org/wiki/Gatun_Lake); [Terrain Tiles (AWS Open Data; SRTM-based elevation)](https://registry.opendata.aws/terrain-tiles/)

### The people who built it
*1904–1914*

Most of the workers came from the Caribbean, and most of those who died were Caribbean too.

More than seventy-five thousand people worked on the American canal; at the peak, about forty thousand at once. Most labourers came from the Caribbean, above all from Barbados. Many stayed, and their descendants are part of Panama today. Pay and life were divided by the gold roll and the silver roll. Gold meant mostly white American staff, paid in US gold dollars. Silver meant mostly Black Caribbean labourers, paid less, in silver currency, with worse housing. Records list between five thousand six hundred and five thousand nine hundred deaths in the American years. Most of the dead were Caribbean workers.

Chapter IV · Step 9 · 1904–1914

#### Gold roll, silver roll

John Stevens began recruiting thousands of workers, especially from the West Indies. The canal administration paid staff on two payrolls. The **gold roll**, paid in gold-backed US dollars, was mostly skilled white Americans. The **silver roll**, paid in silver-backed local currency, was mostly West Indian labourers. The system was tightened between 1905 and 1908 into a racial division of pay, housing, shops, schools and even post-office windows.

#### Deaths on the three projects (estimates)

- 1850–55 Railroad: about 5,000–12,000 (sources disagree)

- 1881–89 French canal: about 22,000

- 1904–14 American canal: 5,609–5,855 recorded, about 350 of them white Americans

In 1907–1913, the years when deaths were recorded by race, 4,668 employees died: 3,788 (81%) classed as “colored” and 900 (19%) as “white”. Worse housing and weaker mosquito protection for silver-roll workers help explain the gap.

All of these numbers are reported or estimated figures. Deaths among people who were not employees, or who left and died later, are not counted.

Sources: [Wikipedia: History of the Panama Canal](https://en.wikipedia.org/wiki/History_of_the_Panama_Canal); [Wikipedia: Gold roll](https://en.wikipedia.org/wiki/Gold_roll); [Wikipedia: Panama Canal Railway](https://en.wikipedia.org/wiki/Panama_Canal_Railway)

## Chapter V · How it works

### The SS Ancon goes through
*15 August 1914*

The canal opened as war broke out in Europe. There was no grand ceremony.

On the fifteenth of August 1914, the steamship Ancon made the first official transit, Atlantic to Pacific. The First World War had just begun, so the planned celebrations became a modest local affair. The canal was finished two years ahead of schedule. What it changed is easy to see. A ship from New York to San Francisco no longer had to go around the tip of South America. A 1913 map put the voyage at about thirteen thousand nautical miles the long way, and about fifty-three hundred through Panama. Press the button to sail both.

Chapter V · Step 10 · 1914

#### Opening, and a shorter world

The canal was officially completed on 1 April 1914; a floating crane from the French era, the *Alexandre La Valley*, had already made the first complete transit on 7 January. The Panama Railroad steamship SS *Ancon* made the first official transit on 15 August 1914. The United States spent about US$375 million, including $10 million to Panama and $40 million to the French company.

- **New York → San Francisco**: 13,135 nmi via the Strait of Magellan (1913 figure)

- **Through the canal**: 5,262 nmi about 9,750 km

- **Saved**: 7,873 nautical miles (about 14,600 km) more than half the voyage

Press “Sail both ships” on the scene. Both ships travel at the same steady speed.

Routes on the globe are drawn approximately. The sailing time shown assumes a constant 12 knots, for comparison only.

Sources: [Wikipedia: History of the Panama Canal](https://en.wikipedia.org/wiki/History_of_the_Panama_Canal); [“Trade Routes and Distances … by the Panama Canal”, 1913 map (University of South Florida, ETC)](https://etc.usf.edu/maps/pages/10400/10479/10479.htm); [Wikipedia: Panama Canal](https://en.wikipedia.org/wiki/Panama_Canal)

### Climbing a water staircase
*How a lock works*

No pumps. Every lift is done by gravity, with water that falls from Gatun Lake.

This is the Gatun flight: three chambers in a row, climbing from the Atlantic to Gatun Lake, about twenty-six metres up. A ship enters the first chamber and the gate behind it closes. The gates meet in a V pointing uphill, so the water pressure pushes them shut. Then valves open in huge tunnels inside the walls. Water from the lake falls through them and wells up through holes in the chamber floor. The chamber fills and the ship rises, until the water matches the next chamber. Only then can the next gate open. Electric locomotives on the walls, called mules, keep the ship centred with cables. The ship moves under its own power. Three steps later the ship floats on Gatun Lake. Every chamber filled has used about a hundred thousand cubic metres of fresh water. Now try it yourself.

Chapter V · Step 11 · The locks

#### A water staircase

Each original chamber is 33.5 m wide and 320 m long. Culverts up to about 6.7 m (22 ft) across run inside the walls; smaller cross culverts under the floor release the water through many openings, which keeps it calm. No pumps are used: the water moves by gravity alone, controlled by valves, and a chamber can be filled in as little as ten minutes.

- Ship enters; the gate behind it closes.

- Filling valves open: lake water falls through the culverts and the chamber rises.

- When the levels match, the gate ahead opens and the ship moves on.

- Going down, drain valves let the water out to the next chamber or the sea.

- **Gatun lift**: ~26 m in three steps

- **Water per chamber**: ~101,000 m³ 26.7 million US gallons

- **Gate leaves**: 14–25 m tall about 2 m thick; hollow, so they float

- **Locks on the route**: Gatun 3 · Pedro Miguel 1 · Miraflores 2 each built as a side-by-side pair

Operate the lock with the button on the scene: it always offers the next safe action, just as interlocks in the real control room prevent opening a gate against a difference in water level. Time is speeded up many times. Lengths are drawn to approximate scale and heights are exaggerated 1.5 times; the ship is a little smaller than a real Panamax vessel so you can see the water.

Sources: [Panama Canal Authority: Design of the locks](https://pancanal.com/en/design-of-the-locks/); [Wikipedia: Panama Canal locks](https://en.wikipedia.org/wiki/Panama_Canal_locks); [Wikipedia: Panama Canal](https://en.wikipedia.org/wiki/Panama_Canal)

## Chapter VI · Whose canal?

### A canal for Panama
*1964 → 1999*

Protests, negotiations and a twenty-year transition brought the canal under Panamanian control.

For decades the Canal Zone was a separate world, with its own police, schools and post offices. Many Panamanians felt it should be theirs. On the ninth of January 1964, students tried to raise Panama’s flag at a Zone high school. Three days of riots followed; about twenty Panamanians and several US soldiers were killed. In 1977 President Jimmy Carter and Panama’s leader Omar Torrijos signed new treaties. The Zone ended in 1979 and the two countries ran the canal together. At noon on the thirty-first of December 1999, Panama took full control. Its Panama Canal Authority has run the canal ever since.

Chapter VI · Step 12 · 1964–1999

#### From Canal Zone to Panama Canal Authority

Tension over sovereignty grew after the Second World War. On 9 January 1964, a dispute over flying Panama’s flag in the Zone led to riots that Panamanians remember as Martyrs’ Day. Reports give about 20–22 Panamanians and 3–5 US soldiers killed. The events are widely seen as a turning point that led to negotiations from 1974.

- 1964 Martyrs’ Day riots (9–11 January)

- 1977 Torrijos–Carter Treaties signed, 7 September

- 1979 Treaties take effect; the Canal Zone ends; joint administration begins

- 1999 Full Panamanian control at noon, 31 December

Under the treaties the United States handed over the canal on condition that Panama guarantee its permanent neutrality, open to ships of all nations. The handover remains debated in US politics; in Panama, it is celebrated as the completion of national sovereignty.

The gold Zone shading fades on the map as the transfer proceeds.

Sources: [Wikipedia: Martyrs’ Day (Panama)](https://en.wikipedia.org/wiki/Martyrs%27_Day_(Panama)); [Wikipedia: History of the Panama Canal](https://en.wikipedia.org/wiki/History_of_the_Panama_Canal); [Wikipedia: Panama Canal](https://en.wikipedia.org/wiki/Panama_Canal)

## Chapter VII · Bigger ships, less rain

### Bigger locks that recycle water
*26 June 2016 · The expanded canal*

A third lane of locks for giant ships, with basins that save water for the next lift.

By the 2000s many ships were too big for the 1914 locks. In 2006 Panamanians approved an expansion in a referendum. The new locks opened on the twenty-sixth of June 2016. Their chambers are four hundred and twenty-seven metres long and fifty-five metres wide, with sliding gates and tugboats instead of mules. Each chamber has three water-saving basins beside it. When the chamber empties, the top layers of water flow into the basins instead of being lost. Next time, that water flows back by gravity. About sixty per cent of the water is reused. Try emptying and filling the chamber.

Chapter VII · Step 13 · 2006–2016

#### Neopanamax locks and water-saving basins

The expansion added new locks at Agua Clara (Atlantic) and Cocolí (Pacific). The first ship through, on 26 June 2016, was the container ship *Cosco Shipping Panama*. The new locks still move water by gravity alone, but each chamber has three basins at stepped heights.

- Emptying: the top slice of water drains into the highest basin, the next slice into the middle basin, the third into the lowest.

- Only the last two slices go down to the next chamber or the sea.

- Filling: the basins drain back in reverse order; only two slices must come from Gatun Lake.

- **Chamber**: 427 × 55 m 18.3 m deep

- **Basins**: 18 3 per chamber

- **Water reused**: ~60% per lockage

- **Estimated cost**: US$5.25 billion contractors sought billions more

Use the buttons on the scene to empty and fill the chamber slice by slice. The 9 m lift divided into five 1.8 m slices is the textbook example; real lifts vary with tides and lake level.

Sources: [Wikipedia: Panama Canal expansion project](https://en.wikipedia.org/wiki/Panama_Canal_expansion_project); [Panama Canal Authority: First water-saving basin filled (2016)](https://pancanal.com/en/first-panama-canal-water-saving-basin-filled-testing-process-begins/); [Wikipedia: Panama Canal](https://en.wikipedia.org/wiki/Panama_Canal)

### When the rain fails
*2023–2026*

Every ship needs lake water to cross. In a drought, the canal has to ration it.

Each ship that passes through uses about two hundred million litres of fresh water from the lake, and it all flows out to the sea. October 2023 was the driest October ever recorded in the canal’s watershed. To save water, the canal cut the number of ships allowed each day from about thirty-six to as few as twenty-two. Queues of ships formed at both ends. In January 2024 the limit began to rise again. The same lake also supplies drinking water to Panama City and Colón. In September 2026, with El Niño expected, the canal capped transits again. A new reservoir on the Indio River is planned to add water for the future.

Chapter VII · Step 14 · 2023–2026

#### Water is the limit

The locks run on rain. In 2023 the canal watershed had its second-driest year on record, and Gatun Lake fell to unusually low levels. The Panama Canal Authority reduced daily transit slots and limited ship draughts to keep enough water in the lake.

- Normal about 36 transits a day

- Dec 2023 22 a day

- 16 Jan 2024 raised to 24 a day

- Sep 2026 capped at 34, then 32 from 15 September, as El Niño threatened

- **Water per transit**: ~200 million L of fresh water, on average

- **Río Indio reservoir**: ~1.25 billion m³ planned; estimated US$1.6 billion

Use the buttons on the scene to compare transit limits. The waiting ships are illustrative.

Sources: [Wikipedia: Panama Canal](https://en.wikipedia.org/wiki/Panama_Canal); [Panama Canal Authority: Daily transits to 24 from January (Dec 2023)](https://pancanal.com/en/panama-canal-to-increase-daily-transits-to-24-starting-in-january/); [Professional Mariner: Panama Canal to slash transits (2023)](https://professionalmariner.com/panama-canal-to-slash-transits-due-to-ongoing-drought/); [Baird Maritime: Panama Canal caps daily transits (2026)](https://www.bairdmaritime.com/shipping/panama-canal-caps-daily-transits-as-el-ni%C3%B1o-threatens-water-levels)

## Epilogue

### A path between the seas
*Today*

Built over four centuries of ambition, by tens of thousands of hands, and still running on rain.

Follow a ship today. From the Caribbean, three steps at Gatun lift it about twenty-six metres into the lake. It crosses the lake and passes through the Culebra Cut, where the mountains were once a hundred and ten metres high. At Pedro Miguel and Miraflores, three more steps lower it to the Pacific. The whole journey takes about half a day. Some thirteen to fourteen thousand ships make it each year. The narrow land that Balboa crossed on foot now carries a share of the world’s trade.

Epilogue · Today

#### A path between the seas

- 1513 Balboa sees the Pacific from the isthmus

- 1855 Panama Railroad opens

- 1881–89 French sea-level attempt fails

- 1903 Panama separates from Colombia; Canal Zone treaty

- 1914 Canal opens, 15 August

- 1964 Martyrs’ Day

- 1977 Torrijos–Carter Treaties

- 1999 Panama takes full control

- 2016 Expanded canal opens

- 2023–24 Drought limits traffic

- **Ships per year**: 13,000–14,000 Panama Canal Authority

- **Connections**: 180+ routes 1,920 ports in 170 countries

- **Workforce**: ~9,000 24 hours a day, every day

- **Share of world trade**: over 5% estimate cited by Wikipedia

The terrain uses SRTM-based elevation data from the AWS Terrain Tiles dataset, exaggerated eight times vertically; the valley under Gatun Lake is reconstructed approximately. Routes on the globe and the illustrative ships are approximate. All full-screen stills are AI-generated to help the imagination; they are not photographs and show no real people. The globe uses NASA Blue Marble imagery.

#### Sources

[USGS: M 7.7, 12 km WSW of Pitaloza Arriba, Panama (9 Oct 2026)](https://earthquake.usgs.gov/earthquakes/eventpage/us6000u18k/executive)
[Associated Press: Two powerful earthquakes rock Panama (9 Oct 2026)](https://www.inquirer.com/news/nation-world/panama-two-earthquakes-aftershocks-canal-20261009.html)
[Wikipedia: Panama Canal](https://en.wikipedia.org/wiki/Panama_Canal)
[Wikipedia: History of the Panama Canal](https://en.wikipedia.org/wiki/History_of_the_Panama_Canal)
[Wikipedia: Panama Canal locks](https://en.wikipedia.org/wiki/Panama_Canal_locks)
[Panama Canal Authority: Design of the locks](https://pancanal.com/en/design-of-the-locks/)
[Panama Canal Authority: History of the Panama Canal](https://pancanal.com/en/history-of-the-panama-canal/)
[Wikipedia: Vasco Núñez de Balboa](https://en.wikipedia.org/wiki/Vasco_N%C3%BA%C3%B1ez_de_Balboa)
[Wikipedia: Panama Canal Railway](https://en.wikipedia.org/wiki/Panama_Canal_Railway)
[Wikipedia: Panama scandals](https://en.wikipedia.org/wiki/Panama_scandals)
[Wikipedia: Separation of Panama from Colombia](https://en.wikipedia.org/wiki/Separation_of_Panama_from_Colombia)
[Wikipedia: Hay–Bunau-Varilla Treaty](https://en.wikipedia.org/wiki/Hay%E2%80%93Bunau-Varilla_Treaty)
[Wikisource: text of the 1903 treaty (Article II)](https://en.wikisource.org/wiki/Hay%E2%80%93Bunau-Varilla_Treaty)
[Wikipedia: Panama Canal Zone](https://en.wikipedia.org/wiki/Panama_Canal_Zone)
[Wikipedia: Health measures during the construction of the Panama Canal](https://en.wikipedia.org/wiki/Health_measures_during_the_construction_of_the_Panama_Canal)
[Wikipedia: Culebra Cut](https://en.wikipedia.org/wiki/Culebra_Cut)
[Wikipedia: Gatun Lake](https://en.wikipedia.org/wiki/Gatun_Lake)
[Wikipedia: Gold roll](https://en.wikipedia.org/wiki/Gold_roll)
[Wikipedia: Martyrs’ Day (Panama)](https://en.wikipedia.org/wiki/Martyrs%27_Day_(Panama))
[Wikipedia: Panama Canal expansion project](https://en.wikipedia.org/wiki/Panama_Canal_expansion_project)
[Panama Canal Authority: First water-saving basin filled (2016)](https://pancanal.com/en/first-panama-canal-water-saving-basin-filled-testing-process-begins/)
[Panama Canal Authority: Daily transits to 24 from January (Dec 2023)](https://pancanal.com/en/panama-canal-to-increase-daily-transits-to-24-starting-in-january/)
[Professional Mariner: Panama Canal to slash transits (2023)](https://professionalmariner.com/panama-canal-to-slash-transits-due-to-ongoing-drought/)
[Baird Maritime: Panama Canal caps daily transits (2026)](https://www.bairdmaritime.com/shipping/panama-canal-caps-daily-transits-as-el-ni%C3%B1o-threatens-water-levels)
[“Trade Routes and Distances … by the Panama Canal”, 1913 map (University of South Florida, ETC)](https://etc.usf.edu/maps/pages/10400/10479/10479.htm)
[Terrain Tiles (AWS Open Data; SRTM-based elevation)](https://registry.opendata.aws/terrain-tiles/)