If any single piece of real estate was believed to hold the key to winning the war, it was the lands surrounding the Dardanelles, the narrow strait separating Europe from Asia in northwestern Turkey. Control of the only waterway between the Black Sea and the Mediterranean Sea was crucial both economically and militarily. Turkey’s entrance into the war in November 1914 placed the Dardanelles squarely in German hands, physically separating the Russian and Allied naval forces and effectively preventing them from cooperating. German control of the strait also meant that Russian wheat could not be shipped to Britain and that British military equipment could be shipped only by means of a treacherous northern route to the Russian ports of Murmansk and Arkhangelsk.
From the time that Turkey entered the war in November 1914, Winston Churchill, first lord of the British Admiralty, began working on a plan to reopen the Dardanelles. The British military leadership believed that this goal could be achieved without ground forces, using naval power alone. Given the significant losses the British army suffered defending France against the Germans, this idea of a navy-only campaign for the Dardanelles was politically important. On November 3, two days after Turkey entered the war, British and French ships made a brief military demonstration by firing on the forts guarding the entrance to the Dardanelles—a symbolic attack that did little actual damage.
After months of planning, but with significant disagreement remaining about objectives, Britain and France launched a naval attack on the Dardanelles on March 18, 1915. A fleet led by sixteen British and French battleships attempted to force its way into the strait, with the goal of opening it by bombarding the dozens of Turkish coastal forts along the way. Although minesweeping ships had been sent ahead to clear a path, five battleships were either sunk or disabled by mines. With about one-third of the British and French battleships lost before the attack was even under way, the remaining ships were pulled back. Allied military commanders changed their objectives and decided instead to send ground forces to take over the Gallipoli Peninsula bordering the northern side of the strait.
After a delay of more than a month, Allied troops—including major contingents from Australia and New Zealand—launched this ground attack, aiming to take Gallipoli completely, using ground forces. The invasion began on April 25, 1915, and the landing proceeded with relative ease. The first Turkish regiments the Allied forces encountered quickly fled the scene, making it seem as if the invasion would be an easy one.
As it turned out, the invasion was far from easy. Turkish forces returned in overwhelming numbers and pushed the Allied troops back to the beaches, where they were trapped with their backs to the sea. They remained entrenched on the beaches until January of the next year, when Britain finally pulled out in defeat. The battle raged for the entire time, with neither side making significant headway, and with losses on both sides in the hundreds of thousands.
Meanwhile, a second struggle between the British and the Turks ensued at the opposite end of the Ottoman Empire, this time for control of the oil fields of Mesopotamia. On November 5, 1914, a force of British and Indian soldiers launched an attack on the major Ottoman port of Basra. They quickly secured not only the port but also the oil fields and pipeline at Abadan, which had been one of the key objectives of the invasion.