The Dardanelles

Every ship that leaves the Black Sea for the open ocean has to pass two Turkish straits, and the Dardanelles is the second and longer of them. Known to the ancient Greeks as the Hellespont, it separates the Gallipoli Peninsula in Europe from the Anatolian mainland in Asia, and in 2025 it logged about 44,500 transits, more than the Bosphorus, according to Turkish maritime authorities. Troy stood near its southern mouth, Persian and Macedonian armies crossed it on bridges of boats, and in 1915 it was the target of one of the First World War's costliest campaigns. Today a single suspension bridge with the longest main span in the world carries traffic high above the water.

The strait runs about 61 kilometers northeast to southwest, from the Sea of Marmara near Gelibolu to the Aegean Sea between Cape Helles and Kumkale. It is between about 1.2 and 6 kilometers wide, narrowing to roughly 1.2 kilometers at the Narrows between the city of Çanakkale on the Asian shore and Kilitbahir on the European side. Average depth is about 55 meters, with a maximum of about 100 meters. A fast surface current carries less salty water from the Black Sea and Marmara toward the Aegean, while denser Mediterranean water flows back beneath it, which complicates navigation at the bends. Turkey runs a vessel traffic service and pilotage scheme for the whole Turkish Straits system, and the 1915 Çanakkale Bridge, opened in March 2022, spans 2,023 meters between its towers.

The strait's modern name comes from the ancient city of Dardanus on its Asian shore. Xerxes crossed it in 480 BCE and Alexander the Great in 334 BCE, and Byzantine and Ottoman rulers later fortified its banks to guard the sea road to Constantinople. In 1915 an Anglo-French fleet failed to force the Narrows, and the land campaign on Gallipoli that followed cost hundreds of thousands of casualties on both sides before the Allies withdrew in January 1916. The 1936 Montreux Convention, which also governs the Bosphorus, guarantees merchant ships free passage in peacetime and restricts warships from non-Black Sea states. Turkey applied its wartime provisions after Russia's full-scale invasion of Ukraine in 2022, and grain, oil and container traffic between the Black Sea and world markets still funnels through here.

• Aegean Sea
  The island-strewn sea where Greek civilization was born connects to
• Mediterranean Sea
  The cradle sea of Western civilization, locked between three continents connects to
• The Achaemenid (Persian) Empire
  The first empire to rule from the Indus to the Aegean, held together by roads and satraps crossed by
• The Ottoman Empire
  Six centuries of rule from Istanbul over the Balkans, Anatolia, the Arab world and North Africa fortified by
• Turkey
  A transcontinental bridge between Europe and Asia located in
• The Bosphorus
  The strait that splits Istanbul between Europe and Asia and is the Black Sea's only door to the oceans paired strait
• Black Sea
  A vast, near-landlocked sea with a lifeless deep route to