Gallipoli

... was a costly and humiliating defeat for the Allied Powers and for the campaign's sponsors, especially Winston Churchill.

Churchill, as First Lord of the Admiralty, first proposed a naval attack on the Dardanelles in November 1914. His plan was based in part on erroneous reports of Ottoman troop strength. Churchill wanted to use a large number of obsolete battleships, which could not compete with the German High Seas Fleet, in a Dardanelles operation, with a small occupation force provided by the army. It was hoped that an attack on the Ottomans would also draw Bulgaria and Greece (both formerly ruled by the Ottomans) into the war on the Allied side.

On 17 February 1915, a British seaplane from HMS Ark Royal flew a reconnaissance sortie over the Straits. Two days later, the first attack on the Dardanelles began when a strong Anglo–French task force, including the British dreadnought HMS Queen Elizabeth, began a long–range bombardment of Ottoman coastal artillery batteries. The initial phase was hampered by a period of bad weather, but by 25 February the outer forts had been reduced and the entrance cleared of mines. After this, Royal Marines were landed to destroy guns at Kum Kale and Seddülbahir, while the naval bombardment shifted to batteries between Kum Kale and Kephez.

Frustrated by the mobility of the Ottoman batteries, Churchill began urging the naval commander, Admiral Sackville Carden, to increase the fleet's efforts. Carden drew up fresh plans and on 4 March sent a cable to Churchill, stating that the fleet could expect to arrive in Istanbul within 14 days. A sense of impending victory was heightened by the interception of a German wireless message, which revealed that the Ottoman forts in the Dardanelles were running out of ammunition. When the message was relayed to Carden, it was agreed that a main attack would be launched on or around 17 March. Carden, suffering from stress, was later placed on the sick list and command was taken over by Admiral John de Robeck.

On 18 March 1915, a fleet of 18 British and French battleships, with an array of cruisers and destroyers, attempted to force its way through the Dardanelles. At their narrowest point, where the straits are only one mile wide, they met accurate shell fire from Turkish shore batteries and an unexpectedly large number of mines. The French battleship Bouvet struck a mine and capsized with her crew of over 600 still aboard. Minesweepers, manned by civilians, retreated under Ottoman artillery fire, leaving the minefields largely intact. HMS Irresistible was sunk by a mine, and HMS Inflexible was withdrawn after being badly damaged. HMS Ocean was sent to rescue Irresistible, but struck a mine and was abandoned, eventually to sink.

The French battleships Suffren and Gaulois sailed through a new line of mines and were damaged. The losses forced de Robeck to sound the "general recall" to protect what remained of his force. Some senior naval officers, including the commander of Queen Elizabeth, Commodore Roger Keyes, felt that they had come close to victory, believing that the Ottoman guns had almost run out of ammunition; but the views of de Robeck, First Sea Lord Jackie Fisher, and others, prevailed. Allied attempts to force the straits using naval power were terminated.

After the failure of the naval attacks, troops were assembled to eliminate the Ottoman mobile artillery. Kitchener appointed General Sir Ian Hamilton to command the 78,000 men of the Mediterranean Expeditionary Force (MEF). Soldiers from the Australian Imperial Force (AIF) and New Zealand Expeditionary Force (NZEF), who were undergoing training in Egypt prior to being deployed in France, were formed into the Australian and New Zealand Army Corps (ANZAC).

Hamilton decided to make two landings, placing the British 29th Division at Cape Helles and the ANZACs on the western side of the Gallipoli peninsula, north of Gaba Tepe, in an area later dubbed Anzac Cove.

The Anzacs landed on 25 April 1915. In that single day they suffered 5,000 casualties. The British landings were equally quickly contained by determined Ottoman troops, and were unable to advance. Trench warfare quickly took hold, mirroring the stalemate on the Western Front. At Anzac Cove it was particularly intensive. Casualties in both locations mounted heavily, and conditions rapidly deteriorated in the summer heat. Sickness was rampant, food quickly became inedible, and there were vast swarms of black corpse flies.

In August a new assault was launched north of Anzac Cove, against the hills around Chunuk Bair. This attack – along with a fresh landing at Suvla Bay – quickly failed, and stalemate returned. Finally, in December, it was decided to evacuate – first Anzac and Suvla, followed by Helles in January 1916.

The Gallipoli campaign gave the Ottoman Empire its only major victory of the war. In Turkey it's regarded as a defining moment in the nation's history, a final surge in the defence of the motherland as the Ottoman Empire crumbled. The struggle formed the basis for the Turkish War of Independence and the declaration of the Republic of Turkey eight years later, with Mustafa Kemal (Kemal Atatürk), who rose to prominence as a commander at Gallipoli, as its first President.

Gallipoli is also commonly considered to be the beginning of Australian and New Zealand national consciousness. 25 April, the anniversary of the landings, is known as ANZAC Day, which surpasses Remembrance Day (Armistice Day) as the most significant commemoration of military casualties and veterans in both countries.