On the 9th of January 1916, the last remaining Allied troops on the Gallipoli peninsula were evacuated.
Find out what went wrong at Gallipoli and why the military aims of the campaign were not achieved and eventually called to a halt.
The Gallipoli campaign took place from 25 April 1915 to 9 January 1916 and was the scene of some of the fiercest fighting of the First World War.
At dawn on 25 April, Allied troops landed on the Gallipoli peninsula in Ottoman Turkey.
The Gallipoli campaign was the land-based element of a strategy intended to allow Allied ships to pass through the Dardanelles, capture Constantinople (now Istanbul) and ultimately knock Ottoman Turkey out of the war.
Troops that landed at Gallipoli faced tough conditions and intense trench fighting.
After months of costly fighting, Allied troops withdrew from Gallipoli in a carefully planned evacuation.
The withdrawal began in December 1915 from Anzac and Suvla, and ended at Cape Helles in January 1916.
Unsanitary conditions including extreme weather, lack of clean water and swarms of flies coupled with unforgiving terrain led to widespread disease.
145,000 of the 213,000 British casualties from the Gallipoli campaign were from illness.
Hear the personal stories from some of the thousands of men who served at Gallipoli recall what conditions there were like.
Listen to their stories in: Why was Gallipoli one of the worst fighting fronts of the First World War?
Allied success in the campaign could have weakened the Central Powers, allowed Britain and France to support Russia and helped to secure British strength in the Middle East. But success depended on Ottoman Turkish opposition quickly crumbling.
General Sir Ian Hamilton decided to make two landings, placing the British 29th Division at Cape Helles and the Australian and New Zealand Army Corps (ANZAC) north of Gaba Tepe in an area later dubbed Anzac Cove. Both landings were quickly contained by determined Ottoman troops, and neither the British nor the Anzacs were able to advance.
Trench warfare quickly took hold at Gallipoli, mirroring the fighting of the Western Front. At Anzac Cove it was particularly intensive. Casualties in both locations mounted heavily, and in the summer heat conditions rapidly deteriorated. 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.
Gallipoli has become a defining moment in the history of both Australia and New Zealand, revealing characteristics that both countries have used to define their soldiers: endurance, determination, initiative and 'mateship'. For the Ottomans, it was a brief respite in the decline of their empire. But through the emergence of Mustafa Kemal (later known as Atatürk) as one of the campaign's leading figures, it also led to the foundation of modern Turkey.
Gallipoli was remembered by the men who fought there as one of the most gruelling places to serve.
Allied troops that landed at Gallipoli and spent months guarding the Dardanelles Straits were faced with brutal conditions and intense fighting.
Hear men who served at Gallipoli recall what conditions they faced during some of the fiercest fighting of the war.
Listen to the podcast: Voices of the First World War: Gallipoli.
Harold Boughton, a former clerk and Royal Fusilier cadet, landed in Gallipoli on 25 August 1915.
His arrival on the peninsula quickly became an abrupt introduction to the reality of the gruelling fighting he would face over the coming months.
He recalls his personal experience of raids on enemy positions, narrow escapes and severe living conditions while serving.
Architect and artist Able Seaman Herbert William Hillier produced over 160 sketches of the scenes he witnessed while serving in Gallipoli.
His collection of sketches, mainly pencil drawings, offer records of events he witnessed throughout the campaign.