Early on the morning of 25 April 1915, Allied forces landed on the Gallipoli peninsula in Ottoman Turkey. The British Army landed at Cape Helles. Troops of the Australian and New Zealand Army Corps (ANZAC) landed north of Gaba Tepe (Kabatepe) headland, on a beach later called 'Anzac Cove'. French troops landed in a feint at Kum Kale on the Dardanelles Asian shore before moving to the Helles sector on Gallipoli.

The Gallipoli Campaign was the land-based element of a broad strategy to defeat the Ottoman Empire.

A large British-French armada had made several attempts to breach Ottoman defences in the Dardanelles but had suffered a decisive defeat on 18 March 1915. A date which is still celebrated in Turkey.

The Allies realised that naval forces alone were unlikely to force a surrender. They hoped that infantry would destroy the shore-based defences. This would bring a victory that would:

Success depended on a quick victory, but this did not occur.

Determined Turkish resistance resulted in protracted trench warfare through the forbidding scrubby slopes and ravines. Fighting in the landings and early battles resulted in heavy casualties on both sides. The unhygienic conditions for soldiers on Gallipoli caused serious illnesses. As the campaign moved into summer, more men were evacuated because of illness than wounds sustained during the conflict.

From the earliest days of the campaign, the Turks clung grimly to the high ground. The Allies could not advance against the higher-positioned Turks. The Turks could not force the Allies back into the sea.

In August 1915, a reinforced Allied force of 11 divisions tried to break the deadlock with an assault on Suvla Bay and diversionary attacks at Helles and Anzac. These actions tried to draw Ottoman reserves away from the main Allied attack on the Sari Bair range, north of Anzac.

At Lone Pine, the Anzacs were successful after days of intense trench fighting. At the Nek, two Australian Light Horse brigades were cut down as they tried to cross no-man's-land and seize the Ottoman trenches.

Soon afterwards, the New Zealanders launched an assault against the hills around Chunuk Bair, north of Anzac Cove. Both this attack and the British landing at Suvla Bay failed.

The battle returned to a stalemate.

Finally, British commanders decided to evacuate. First Anzac Cove and Suvla Bay on 20 December 1915. Then Helles in January 1916.

Overall the Gallipoli campaign was unsuccessful for the Allies. However the battles fought on Gallipoli established the great military reputation of the original Anzacs. From this tragic campaign a rare phenomenon of friendship grew between Australia, New Zealand and Turkey and continues to date.