Anzac Day

The Gallipoli Campaign took place during World War I on the Gallipoli peninsula in the Ottoman Empire (modern Turkey), between 25 April 1915 and 9 January 1916. The British and French aimed to secure a sea route to Russia. They launched a naval campaign to force a passage through the Dardanelles. After the naval operation, an amphibious landing was undertaken on the Gallipoli peninsula, to capture the Ottoman capital of Constantinople (Istanbul). After eight months the land campaign had failed, with many casualties on both sides, and the invasion force was withdrawn to Egypt.

The Gallipoli campaign was one of the greatest Ottoman victories during the war and is considered a major failure of the Allies. In Turkey, it is perceived 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 founding of the Republic of Turkey eight years later under Mustafa Kemal Atatürk, a commander at Gallipoli.

The campaign marks the birth of national consciousness in Australia and New Zealand, and the date of the landing, 25 April, is known as "Anzac Day". It remains the most significant commemoration of military casualties and veterans, surpassing Remembrance Day (Armistice Day).

The film version of the event, Gallipoli, was made by Peter Weir in 1981. It stars a remarkably youthful Mel Gibson, as well as Mark Lee, Bill Kerr, and Harold Hopkins.

Here's a short documentary which should fill in a few details for you.