# The Turkish Straits > On 28 October 2026 three naval drones struck the container ship Contship Jet off Bulgaria, on its way to Romania, as the defence ministers of Bulgaria, Romania and Türkiye met on Black Sea security. This film explains the geography and law behind every ship in that sea: why the Black Sea's only link to the oceans is a chain of two narrow straits and the Sea of Marmara; how fresh water flows out on top while salty water flows in underneath; why empires from the Persians to the Ottomans fought to hold them; how the Treaty of Lausanne placed them under an international commission in 1923; what the Montreux Convention of 1936 says about merchant ships and warships; how Türkiye applied it in 2022 after Russia invaded Ukraine; and why the straits remain one of the world's busiest waterways. Interactive film: https://www.planetpast.com/stories/the-turkish-straits/ Publisher: PlanetPast (https://www.planetpast.com/) · d => T('readPublished', l, { d: dateIn(d, l) }) 2026-10-29 · History, Earth science, Society ## Prologue ### The narrow door to the Black Sea *History · Earth · Society* Two straits, one treaty, every ship. On 28 October 2026, three naval drones struck the container ship Contship Jet in the Black Sea, off Bulgaria, on its way from Haifa in Israel to Constanța in Romania. Its crew abandoned ship in life rafts, and the ship was left listing, with containers lost overboard. Weeks earlier, drones had hit two other ships in Bulgaria's exclusive economic zone. Bulgaria's defence minister announced this attack at a meeting on Black Sea security; Bulgaria did not say who was responsible. Every ship that sails into that sea from the oceans, whatever its cargo, comes through the same narrow door. This film is about that door: the Turkish Straits. - **3**: naval drones, according to Bulgaria’s defence minister - **Haifa → Constanța**: its route ![The Black Sea has no other outlet to the oceans: every ship in or out passes this way. AI-generated still.](https://assets.planetpast.com/a/00/0019085b48f56cc6.jpg) - 6 Oct: Two ships hit in Bulgaria’s zone; one sinks - 28 Oct: Contship Jet struck off Cape Kaliakra - 28 Oct: Bulgaria, Romania, Turkey agree a joint security mechanism ![Six countries touch the Black Sea: Turkey, Bulgaria, Romania, Ukraine, Russia and Georgia. AI-generated still.](https://assets.planetpast.com/a/2e/2e31c41f17c4cee4.jpg) - A sea with only one way out - Two currents flowing opposite ways - Empires and wars at the straits - The Montreux rules for warships and trade Prologue #### Drones off Bulgaria Sofia Globe, 28 October 2026: the Liberian-flagged container ship Contship Jet, sailing from Haifa to Constanța, was attacked about 16 nautical miles off Cape Kaliakra (21 miles from Shabla, according to Defence Minister Dimitar Stoyanov), by three drones according to Stoyanov; the crew took to life rafts and abandoned ship, and the vessel was listing. The article says it is widely believed that Russia is behind the attacks, while Bulgaria’s government is reluctant to assign blame. The 16-mile figure is Maritime.bg’s, as cited by Sofia Globe; Stoyanov and UNITED24 give about 21 miles. UNITED24: Stoyanov announced the attack while meeting his counterparts from Romania and Türkiye in Sofia; the three condemned drone attacks on commercial shipping and agreed a trilateral coordination mechanism. KSAT/AP, 6 October 2026: drones hit two vessels about 128 km off Bulgaria; the Alfa Watan sank and the Able caught fire. Ukraine’s President Zelenskyy blamed Russia; Russian officials had not commented, and Bulgarian authorities said the origin of the drones was under investigation. Claims about who carried out attacks are reported as each party made them; this film does not assign blame. The 3D map is a teaching model: coastlines are simplified and depths and widths are exaggerated so the straits can be seen. Sources: [Sofia Globe (28 Oct 2026): drone attack on container ship off Bulgaria’s Cape Kaliakra](https://sofiaglobe.com/2026/10/28/drone-attack-on-container-ship-off-bulgarias-cape-kaliakra/); [UNITED24 Media (28 Oct 2026): naval drones strike ship off Bulgaria as three NATO defence ministers meet](https://united24media.com/world/naval-drones-strike-ship-off-bulgaria-as-three-nato-defense-ministers-meet-23888); [KSAT, from the Associated Press (6 Oct 2026): Bulgaria’s leader says drone attack hits two commercial vessels](https://www.ksat.com/news/2026/10/06/bulgarias-leader-says-drone-attack-hits-2-commercial-vessels-and-ukraines-president-blames-russia/) ## Chapter I · A sea with one door ### A sea with one door *Chapter I* Two straits and a small sea between. The Black Sea is almost closed. Its only link to the world's oceans is a chain: the Bosporus, the small Sea of Marmara, and the Dardanelles, which opens into the Aegean and the Mediterranean. The Bosporus is up to thirty kilometres long and only seven hundred and fifty metres wide at its narrowest. The Dardanelles runs sixty-one kilometres, between just over one and six kilometres wide. Both lie entirely inside Turkey, so one country holds both banks of the door. Sail a ship out of the Black Sea. ![Two narrow straits, with the Sea of Marmara between them. AI-generated still.](https://assets.planetpast.com/a/3d/3d8d2015840ac6d3.jpg) ![Two fifteenth-century fortresses face each other across the narrows, built to close the water to the city between them. AI-generated still.](https://assets.planetpast.com/a/2b/2ba79aba094e2fc0.jpg) - Bosporus: 0.75–3.7 km wide: ~30 - Dardanelles: 1.2–6 km wide: 61 - **65 m**: Bosporus, on average (max 124 m) - **55 m**: Dardanelles, on average (max 103 m) - Bosporus: Istanbul on both shores - Dardanelles: the Gallipoli peninsula and Anatolia Chapter I · A sea with one door #### The chain of straits Wikipedia, Bosporus: up to 30 km long, 750 m wide at its narrowest and 3.7 km at its widest (the text gives 700 m and 3,420 m), with an average depth of 65 m and a maximum of 124 m; it links the Black Sea to the Sea of Marmara and forms part of the boundary between Europe and Asia. Wikipedia, Dardanelles: 61 km long and 1.2 to 6 km wide, averaging 55 m deep with a maximum of 103 m near Çanakkale; it links the Sea of Marmara with the Aegean Sea. Try it: the ship follows the only route out, through both straits; the map is simplified and its widths exaggerated. The 3D map is a teaching model: coastlines are simplified and depths and widths are exaggerated so the straits can be seen. Sources: [Wikipedia: Bosporus](https://en.wikipedia.org/wiki/Bosporus); [Wikipedia: Dardanelles](https://en.wikipedia.org/wiki/Dardanelles) ### The Bosporus runs through the middle of a city. In 330, the Roman emperor Constantine refounded the Greek city of Byzantium here as Constantinople, and today Istanbul spreads over both banks, one in Europe and one in Asia. The strait is part of the boundary between the two continents. Its Greek name was later explained as the cattle crossing, after a myth of Io, who crossed it as a cow. Three bridges and two tunnels now cross the Bosporus, and since 2022 a long suspension bridge spans the Dardanelles too. Yet the ships keep passing underneath. ![A walled city on a peninsula beside the strait. AI-generated still.](https://assets.planetpast.com/a/c1/c1199f90d903f1f5.jpg) ![Two tunnels also run under the strait: one carries trains, the other cars. AI-generated still.](https://assets.planetpast.com/a/57/57a01ff71f7f03c3.jpg) - 1973: 15 July Martyrs Bridge - 1988: Fatih Sultan Mehmet Bridge - 2016: Yavuz Sultan Selim Bridge - Mar 2022: Çanakkale 1915 Bridge, over the Dardanelles ![Ships still pass beneath every crossing. AI-generated still.](https://assets.planetpast.com/a/8f/8f0bf9e9ddec55c4.jpg) Chapter I · A sea with one door #### A city on a strait Wikipedia, Bosporus: Constantine the Great founded Constantinople on the strait in AD 330; Istanbul lies on both banks. Three bridges (the 15 July Martyrs Bridge of 1973, the Fatih Sultan Mehmet Bridge of 1988 and the Yavuz Sultan Selim Bridge of 2016), one undersea road tunnel and one railway tunnel connect the banks. Wikipedia, Dardanelles: the Çanakkale 1915 Bridge opened in March 2022, joining Lapseki on the Asian side with Sütlüce on the European side. The 3D map is a teaching model: coastlines are simplified and depths and widths are exaggerated so the straits can be seen. Sources: [Wikipedia: Bosporus](https://en.wikipedia.org/wiki/Bosporus); [Wikipedia: Dardanelles](https://en.wikipedia.org/wiki/Dardanelles) ## Chapter II · Two rivers in one ### Two rivers in one *Chapter II* Fresh water out on top, salt water in below. The water in the Bosporus moves two ways at once. At the surface, fresher water from the Black Sea flows south, about sixteen thousand cubic metres every second. Underneath, saltier, heavier water from the Mediterranean side creeps north along the bottom, about eleven thousand cubic metres a second. Two rivers, stacked on top of each other, flowing in opposite directions. In 1680, the Italian scientist Luigi Ferdinando Marsigli explained it with a box of two waters of different density joined by two holes. The heavy water ran out at the bottom, the light water at the top. Compare his box with the strait. - Surface, southward (fresher): ~16,000 - Bottom, northward (saltier): ~11,000 - Salty water is denser, so it sinks - Fresher water floats on top - The difference drives both currents - **1681**: his book on the Bosporus published, a year after his study ![Density does the work, not wind: so many rivers empty into the Black Sea that its water is the fresher of the two. AI-generated still.](https://assets.planetpast.com/a/46/4617490ff525f92a.jpg) Chapter II · Two rivers in one #### A strait with two currents Wikipedia, Bosporus: fresher water flows south at the surface at about 16,000 m³/s, while saltier water flows north near the bottom at about 11,000 m³/s. The Oceanography Society: Luigi Ferdinando Marsigli studied the Bosporus currents in 1680 and published in 1681; he built a two-compartment box joined by openings at top and bottom, and water of different densities flowed in opposite directions, which he took as the cause of the strait’s currents. Try it: “Marsigli’s box” shows his experiment; “the strait” shows the same two layers along the Bosporus. Not to scale. The 3D map is a teaching model: coastlines are simplified and depths and widths are exaggerated so the straits can be seen. Sources: [Wikipedia: Bosporus](https://en.wikipedia.org/wiki/Bosporus); [Oceanography (The Oceanography Society): the Bosporus Strait, a special place in the history of oceanography](https://tos.org/oceanography/article/the-bosporus-strait-a-special-place-in-the-history-ofoceanography) ### Those currents make the Bosporus hard to sail. In places ships must swing through forty-five degrees against a current of up to eight knots, about fifteen kilometres an hour, and at one bend through eighty degrees, with the view ahead blocked. Still, the traffic is enormous. In 2024, 41,363 vessels passed through the Bosporus, more than a hundred a day, including over nine thousand tankers. Only thirty-two were warships. ![A tanker turns between waterfront houses. AI-generated still.](https://assets.planetpast.com/a/47/4790fdb9575e4d13.jpg) - **45°**: Kandilli to Aşiyan, currents of 7–8 knots (about 13–15 km/h) - **80°**: at Yeniköy, with the view blocked - General cargo: 15,490 - Bulk carriers: 8,777 - Tankers (incl. 2,910 chemical): 9,143 - Container ships: 3,533 - **41,363**: about 113 a day Chapter II · Two rivers in one #### Busy and dangerous Wikipedia, Bosporus: between Kandilli Point and Aşiyan ships must alter course by 45 degrees where currents can reach 7 to 8 knots; at Yeniköy the alteration is 80 degrees and sight lines are blocked. Hürriyet Daily News: 41,363 vessels passed through the Bosporus in 2024, including 6,233 tankers and 2,910 chemical tankers, 15,490 general cargo ships, 8,777 bulk carriers and 3,533 container ships. 41,363 ÷ 366 ≈ 113 a day. The 3D map is a teaching model: coastlines are simplified and depths and widths are exaggerated so the straits can be seen. Sources: [Wikipedia: Bosporus](https://en.wikipedia.org/wiki/Bosporus); [Hürriyet Daily News (Feb 2025): 41,363 ships traversed Bosphorus last year](https://hurriyetdailynews.com/41-363-ships-traversed-bosphorus-last-year-205531) ## Chapter III · Empires at the door ### Empires at the door *Chapter III* Whoever holds the straits holds the crossing. A strait is both a road for ships and a crossing for armies. The Greeks called the Dardanelles the Hellespont, and according to Herodotus, the Persian king Xerxes bridged it with boats to march his army into Europe in 480 BC. A storm wrecked his first bridges, and they had to be built again. Over the centuries, Rome and its eastern heir, the Byzantine Empire, ruled the straits from Constantinople. On 29 May 1453 the Ottoman sultan Mehmed the Second captured the city and made it his capital. Whoever held the banks could open the door, or close it. - **~482 BC**: two pontoon bridges built at Abydos - **480 BC**: the army crosses - **Hellespontos**: “Sea of Helle”, from the Golden Fleece myth ![Warships at anchor beside an Ottoman city, in the style of a 19th-century painting. AI-generated still.](https://assets.planetpast.com/a/2e/2edf8f2ef585929a.jpg) ![Herodotus writes that when a storm broke the first bridges, Xerxes had the water itself whipped. AI-generated still.](https://assets.planetpast.com/a/38/388940d11b84bfce.jpg) Chapter III · Empires at the door #### The Hellespont Wikipedia, Dardanelles: the ancient Greek name Hellespontos means “Sea of Helle”, after Helle, who drowned there in the Golden Fleece myth. Herodotus says Xerxes I had two pontoon bridges built at Abydos around 482 BC; a storm destroyed them, and the army crossed in 480 BC. Wikipedia, Bosporus: Constantinople, founded in AD 330, stood on the Bosporus. Wikipedia, Fall of Constantinople: the Ottoman Empire captured the city on 29 May 1453 under Sultan Mehmed II, effectively ending the Byzantine Empire, and Mehmed made it the Ottoman capital. The idea that holding the banks lets a power open or close the straits is a summary of the history told in this chapter. The 3D map is a teaching model: coastlines are simplified and depths and widths are exaggerated so the straits can be seen. Sources: [Wikipedia: Dardanelles](https://en.wikipedia.org/wiki/Dardanelles); [Wikipedia: Bosporus](https://en.wikipedia.org/wiki/Bosporus); [Wikipedia: Fall of Constantinople](https://en.wikipedia.org/wiki/Fall_of_Constantinople) ### In the First World War the Ottoman Empire mined the straits. In 1915 the Allies, led by Britain and France, tried to force them open at Gallipoli. Turkish troops pinned the Allied soldiers on the peninsula's coasts, and after eight months of fighting, the British government ordered a withdrawal. After the war the Ottoman Empire gave way to the Republic of Turkey, and the Treaty of Lausanne of 1923 demilitarised the Dardanelles, so no forts could guard them, and put the straits under an International Straits Commission of the League of Nations. Compare an open door with a supervised one. - **8 months**: of fighting, 1915 - **Dec 1915**: withdrawal ordered by the British cabinet ![The Dardanelles run about sixty-one kilometres and narrow to roughly one and a quarter at the tightest point. AI-generated still.](https://assets.planetpast.com/a/c0/c05ebc19f4f7e8d4.jpg) - The Dardanelles demilitarised - An International Straits Commission - Under the League of Nations - **1936**: a new treaty replaces the commission Chapter III · Empires at the door #### From Gallipoli to Lausanne Wikipedia, Dardanelles: in 1915 Allied forces attacked to open the straits; Turkish troops held them on the peninsula’s coasts, and the British cabinet ordered a withdrawal in December 1915 after eight months of fighting. Wikipedia, Montreux Convention: the Treaty of Lausanne (1923) demilitarised the Dardanelles and placed the straits under the League of Nations’ International Straits Commission; the 1936 Convention abolished the Commission. The Gallipoli campaign is told more fully in PlanetPast’s film on the Ottoman Empire. Try it: “open” shows unarmed banks; “commission” adds the international supervisors of 1923. No battle is shown. The 3D map is a teaching model: coastlines are simplified and depths and widths are exaggerated so the straits can be seen. Sources: [Wikipedia: Dardanelles](https://en.wikipedia.org/wiki/Dardanelles); [Wikipedia: Montreux Convention Regarding the Regime of the Straits](https://en.wikipedia.org/wiki/Montreux_Convention_Regarding_the_Regime_of_the_Straits) ## Chapter IV · The rules of 1936 ### The rules of 1936 *Chapter IV* Free for trade, limited for warships. In 1936, in the Swiss town of Montreux, Turkey and nine other countries signed a new treaty. Turkey regained control of the straits, and the right to fortify them again. The international commission of 1923 was abolished. For trade, the rule is simple. In peacetime, merchant ships of any flag have complete freedom of passage, by day and by night. That is why the Contship Jet, and tens of thousands of ships a year, can sail through. - **20 Jul 1936**: signed - **9 Nov 1936**: in force - **10**: signatory countries - Turkey, Bulgaria, Romania, Greece, Yugoslavia - The Soviet Union, the United Kingdom, France - Australia, Japan > Complete freedom of transit and navigation in the Straits, by day and by night, under any flag. (Montreux Convention, Article 2, for merchant ships in peacetime) ![The convention was written with no expiry date, though any party may give notice that it wants the text revised. AI-generated still.](https://assets.planetpast.com/a/94/94789e9f80dde944.jpg) Chapter IV · The rules of 1936 #### Montreux, 1936 Wikipedia, Montreux Convention: signed at Montreux on 20 July 1936 and in force from 9 November 1936, by Australia, Bulgaria, France, Greece, Japan, Romania, Yugoslavia, Turkey, the United Kingdom and the Soviet Union. Turkey regained military control of the straits and could refortify the Dardanelles. Article 2 gives merchant ships in peacetime “complete freedom of transit and navigation in the Straits, by day and by night, under any flag” (treaty text). The 3D map is a teaching model: coastlines are simplified and depths and widths are exaggerated so the straits can be seen. Sources: [Wikipedia: Montreux Convention Regarding the Regime of the Straits](https://en.wikipedia.org/wiki/Montreux_Convention_Regarding_the_Regime_of_the_Straits); [Hürriyet Daily News (Feb 2025): 41,363 ships traversed Bosphorus last year](https://hurriyetdailynews.com/41-363-ships-traversed-bosphorus-last-year-205531) ### Warships are another matter. A foreign navy must warn Turkey before sending one through: eight days ahead for Black Sea countries, fifteen for everyone else. No more than nine foreign warships may be in transit at once. Navies from outside the Black Sea face tighter limits: no more than forty-five thousand tons of their warships in the Black Sea at any time, and a stay of no more than twenty-one days. Only Black Sea countries may send their largest warships through. The treaty never names aircraft carriers, but Turkey reads it as excluding them, and modern carriers are far too heavy anyway. So the treaty favours the countries that border the Black Sea. Send a warship from each side and see the rules applied. - **8 days**: Black Sea states - **15 days**: all others - **9**: foreign warships in transit at once, at most - All such navies together: 45,000 - Any one country: 30,000 - Largest single ship in transit: 10,000 - **21 days**: longest stay for outside navies - Capital ships of any tonnage, with escorts - Submarines, with notice, if built or repaired abroad - **not named**: in the 1936 text: a Turkish reading, not an explicit ban Chapter IV · The rules of 1936 #### Warships under Montreux Wikipedia, Montreux Convention: the normal notice for a warship transit is 8 days, and the treaty says 15 days is desirable for non-Black Sea powers; up to 9 foreign warships may be in transit at once, with an aggregate of 15,000 tons, and no single ship over 10,000 tons may pass. The treaty text sets an aggregate of 30,000 tons for warships of non-Black Sea powers in the Black Sea, which may rise to at most 45,000 tons in some circumstances; Wikipedia reads this as no single nation above 30,000 tons. They and may stay at most 21 days. Only Black Sea states may transit capital ships of any tonnage, escorted by up to two destroyers, and may send submarines with prior notice if they were built, bought or repaired outside the Black Sea. The treaty has no explicit ban on aircraft carriers; Turkey cites it as prohibiting them. The “tilt” towards littoral states is this film’s summary of those rules. Try it: the readout applies the notice, tonnage and time rules to a warship from a Black Sea state and from outside. The 3D map is a teaching model: coastlines are simplified and depths and widths are exaggerated so the straits can be seen. Sources: [Wikipedia: Montreux Convention Regarding the Regime of the Straits](https://en.wikipedia.org/wiki/Montreux_Convention_Regarding_the_Regime_of_the_Straits) ## Chapter V · War and the straits ### War and the straits *Chapter V* The treaty’s wartime clauses, used. The treaty also covers war. If Turkey is not at war itself, warships of the countries fighting may not pass, except to return to their home bases. After Russia invaded Ukraine, Turkey called it a war on 27 February 2022. That word switched on the wartime rule, and Turkey closed the straits to warships. Its foreign minister said ships returning to bases in the Black Sea could still pass. Turkey turned back Russian warships that February and again that October, and in January 2024 also refused two minehunters that Britain had given to Ukraine: the rule applies to both sides. Try a warship heading home, and one heading in. - Warships of the warring sides may not pass - Except to return to their home bases - If Turkey itself is at war or threatened: its own decision > If the warship is returning to its base in the Black Sea, the passage is not closed. (Turkish Foreign Minister Mevlüt Çavuşoğlu, February 2022) ![Turkey decides for itself when the wartime article applies; no other party can switch it on. AI-generated still.](https://assets.planetpast.com/a/e1/e18c317716214d04.jpg) - 27 Feb 2022: Turkey calls the invasion a war - Feb 2022: Three of four Russian warships refused - Oct 2022: Two more Russian warships refused - 2 Jan 2024: Two minehunters for Ukraine refused ![Submarines of states outside the Black Sea may not pass through at all under the convention. AI-generated still.](https://assets.planetpast.com/a/88/8802235733da5317.jpg) Chapter V · War and the straits #### Montreux in wartime Wikipedia, Montreux Convention: when Turkey is not a belligerent, warships of belligerent powers may not pass except to return to their base; when Turkey is at war or threatened, it may decide on warship passage as it sees fit. After Russia’s invasion of Ukraine, Turkey called it a “war” on 27 February 2022; around 27–28 February it refused three of four Russian warships, in October 2022 it refused the Varyag and Admiral Tributs, and on 2 January 2024 it refused two British-donated minehunters bound for Ukraine. USNI News: Foreign Minister Mevlüt Çavuşoğlu said, “If the warship is returning to its base in the Black Sea, the passage is not closed”, and that Turkey could restrict warships of warring states while not itself a belligerent. Try it: a warship heading home is let through; one heading into the Black Sea is stopped. Ships are generic. Claims about who carried out attacks are reported as each party made them; this film does not assign blame. The 3D map is a teaching model: coastlines are simplified and depths and widths are exaggerated so the straits can be seen. Sources: [Wikipedia: Montreux Convention Regarding the Regime of the Straits](https://en.wikipedia.org/wiki/Montreux_Convention_Regarding_the_Regime_of_the_Straits); [USNI News (28 Feb 2022): Turkey closes Bosphorus, Dardanelles straits to warships](https://news.usni.org/2022/02/28/turkey-closes-bosphorus-dardanelles-straits-to-warships) ### Merchant ships are treated differently. Under the treaty they kept passing the straits, and that trade is what made the Black Sea's shipping lanes so busy, and so exposed. But the treaty governs the straits, not the open sea beyond them. The ships attacked this October were out at sea, beyond the straits. On 6 October one of them sank, and two sailors were flown to hospital; another, carrying wheat, caught fire. Bulgaria's prime minister said such attacks disrupt shipping and raise insurance costs. ![Grain pours into a bulk carrier. AI-generated still.](https://assets.planetpast.com/a/58/58f2fa1893166388.jpg) - Passage through the Bosporus and Dardanelles - Warships’ numbers, tonnage and stays - Not: what happens out at sea - **~128 km**: 6 October attacks - **~16 nmi**: Contship Jet, 28 October - **3**: countries in a new Black Sea security mechanism: Bulgaria, Romania, Turkey Chapter V · War and the straits #### Beyond the straits Wikipedia, Montreux Convention: Article 2 guarantees merchant ships passage through the straits in peacetime, and the treaty’s warship clauses govern transit and stays. The convention regulates passage through the straits; incidents in the open Black Sea fall outside it. KSAT/AP, 6 October 2026: the two ships were hit about 128 km off Bulgaria; Prime Minister Rumen Radev said the attacks were disrupting Black Sea shipping, raising insurance costs and increasing the risk of wider conflict. Sofia Globe: the Contship Jet was about 16 nautical miles off Cape Kaliakra. UNITED24: Bulgaria, Romania and Türkiye agreed a trilateral coordination mechanism covering consultations, intelligence sharing, maritime surveillance and early warning. Claims about who carried out attacks are reported as each party made them; this film does not assign blame. The 3D map is a teaching model: coastlines are simplified and depths and widths are exaggerated so the straits can be seen. Sources: [Wikipedia: Montreux Convention Regarding the Regime of the Straits](https://en.wikipedia.org/wiki/Montreux_Convention_Regarding_the_Regime_of_the_Straits); [KSAT, from the Associated Press (6 Oct 2026): Bulgaria’s leader says drone attack hits two commercial vessels](https://www.ksat.com/news/2026/10/06/bulgarias-leader-says-drone-attack-hits-2-commercial-vessels-and-ukraines-president-blames-russia/); [Sofia Globe (28 Oct 2026): drone attack on container ship off Bulgaria’s Cape Kaliakra](https://sofiaglobe.com/2026/10/28/drone-attack-on-container-ship-off-bulgarias-cape-kaliakra/); [UNITED24 Media (28 Oct 2026): naval drones strike ship off Bulgaria as three NATO defence ministers meet](https://united24media.com/world/naval-drones-strike-ship-off-bulgaria-as-three-nato-defense-ministers-meet-23888) ## Epilogue ### The narrow door *Epilogue* Geography made it; a treaty runs it. Geography made the Turkish Straits a single narrow door, with two currents running through it in opposite directions. History made it a prize that empires fought over. Since 1936, a short treaty has kept it open to trade and narrow for warships, even in wartime. Every ship that sails in from the oceans comes through it, under rules written in a Swiss town ninety years ago. - 480 BC: Xerxes crosses the Hellespont - AD 330: Constantinople founded - 1680: Marsigli explains the two currents - 1915: Gallipoli - 1923: Lausanne: an international commission - 1936: Montreux Convention - 2022: Straits closed to warships - 2026: Drone attacks on merchant ships at sea ![Under the convention, taking a Turkish pilot through the strait is offered, not required. AI-generated still.](https://assets.planetpast.com/a/a8/a895b31148e3c625.jpg) - **90 years**: since Montreux was signed - **2**: straits: the Bosporus and the Dardanelles - **1**: treaty for both, and for the Sea of Marmara between Epilogue #### Sources and notes Every figure in this film comes from the sources below, which were read for it. Claims about who carried out the 2026 attacks are reported as each party made them; the film does not assign responsibility. The 3D map is simplified and not to scale. All stills are AI-generated illustrations, not photographs of real ships, places or events. Sources: [Sofia Globe (28 Oct 2026): drone attack on container ship off Bulgaria’s Cape Kaliakra](https://sofiaglobe.com/2026/10/28/drone-attack-on-container-ship-off-bulgarias-cape-kaliakra/); [UNITED24 Media (28 Oct 2026): naval drones strike ship off Bulgaria as three NATO defence ministers meet](https://united24media.com/world/naval-drones-strike-ship-off-bulgaria-as-three-nato-defense-ministers-meet-23888); [KSAT, from the Associated Press (6 Oct 2026): Bulgaria’s leader says drone attack hits two commercial vessels](https://www.ksat.com/news/2026/10/06/bulgarias-leader-says-drone-attack-hits-2-commercial-vessels-and-ukraines-president-blames-russia/); [Wikipedia: Bosporus](https://en.wikipedia.org/wiki/Bosporus); [Wikipedia: Dardanelles](https://en.wikipedia.org/wiki/Dardanelles); [Oceanography (The Oceanography Society): the Bosporus Strait, a special place in the history of oceanography](https://tos.org/oceanography/article/the-bosporus-strait-a-special-place-in-the-history-ofoceanography); [Hürriyet Daily News (Feb 2025): 41,363 ships traversed Bosphorus last year](https://hurriyetdailynews.com/41-363-ships-traversed-bosphorus-last-year-205531); [Wikipedia: Fall of Constantinople](https://en.wikipedia.org/wiki/Fall_of_Constantinople); [Wikipedia: Montreux Convention Regarding the Regime of the Straits](https://en.wikipedia.org/wiki/Montreux_Convention_Regarding_the_Regime_of_the_Straits); [USNI News (28 Feb 2022): Turkey closes Bosphorus, Dardanelles straits to warships](https://news.usni.org/2022/02/28/turkey-closes-bosphorus-dardanelles-straits-to-warships)