Marking the day that the Australian and New Zealand Armed Corps (ANZAC) landed on the Gallipoli Peninsula in 1915, the 25th of April is one of the most important national days in both Australia and New Zealand. Known as Anzac Day, it commemorates those who fought and lost their lives during the first major military action of World War I to involve Australian and New Zealand forces.

Both countries were relatively new nations when World War I broke out in 1914 and were eager to establish a reputation on the international stage. Australian and New Zealand soldiers were charged with capturing the Gallipoli Peninsula in order to open the Dardanelles to the Allied navies.

Their ultimate aim was to capture Constantinople (modern-day Istanbul), which served as the capital of the Ottoman Empire, a powerful German ally. Both sides suffered heavy casualties during the eight-month Gallipoli campaign and it resulted in an eventual withdrawal of the ANZAC troops. But it left a powerful legacy and the “Anzac legend” has become an integral part of Australian and New Zealander identity.

The first Anzac Day commemorations were held on 25 April 1916 with ceremonies and services across Australia and New Zealand that saw convoys of cars carrying wounded soldiers through the streets. More than 2,000 Australian and New Zealand troops paraded through London and were dubbed by one London newspaper as the “Knights of Gallipoli”. For the remainder of the war, Anzac Day was marked by recruiting campaigns and patriotic rallies as a national identity developed.

By the end of the war, around 60,000 Australians and 18,000 New Zealanders had lost their lives and Anzac Day was declared a public holiday as a national day of remembrance. The rituals currently associated with Anzac Day were established by around the mid-1930s, including dawn vigils, memorial services and reunions where war veterans would play games of two-up together.

In the wake of World War II, Anzac Day also became a moment to commemorate those who fought in this new world war. In subsequent years it has broadened to include any Australian or New Zealander that has lost their lives in military or peacekeeping operations for their country.