Anzac Day is a national day of remembrance in Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 and New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

, commemorated by both countries on 25 April every year to honour the members of the Australian and New Zealand Army Corps

Australian and New Zealand Army Corps

The Australian and New Zealand Army Corps was a First World War army corps of the Mediterranean Expeditionary Force that was formed in Egypt in 1915 and operated during the Battle of Gallipoli. General William Birdwood commanded the corps, which comprised troops from the First Australian Imperial...

 (ANZAC) who fought at Gallipoli

Battle of Gallipoli

The Gallipoli Campaign, also known as the Dardanelles Campaign or the Battle of Gallipoli, took place at the peninsula of Gallipoli in the Ottoman Empire between 25 April 1915 and 9 January 1916, during the First World War...

 in the Ottoman Empire

Ottoman Empire

The Ottoman EmpireIt was usually referred to as the "Ottoman Empire", the "Turkish Empire", the "Ottoman Caliphate" or more commonly "Turkey" by its contemporaries...

 during World War I

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

. It now more broadly commemorates all those who died and served in military operations for their countries. Anzac Day is also observed in the Cook Islands

Cook Islands

The Cook Islands is a self-governing parliamentary democracy in the South Pacific Ocean in free association with New Zealand...

, Niue

Niue

Niue , is an island country in the South Pacific Ocean. It is commonly known as the "Rock of Polynesia", and inhabitants of the island call it "the Rock" for short. Niue is northeast of New Zealand in a triangle between Tonga to the southwest, the Samoas to the northwest, and the Cook Islands to...

, and Tonga

Tonga

Tonga, officially the Kingdom of Tonga , is a state and an archipelago in the South Pacific Ocean, comprising 176 islands scattered over of ocean in the South Pacific...

. It is no longer observed as a national holiday in Samoa

Samoa

Samoa , officially the Independent State of Samoa, formerly known as Western Samoa is a country encompassing the western part of the Samoan Islands in the South Pacific Ocean. It became independent from New Zealand in 1962. The two main islands of Samoa are Upolu and one of the biggest islands in...

.
Anzac Day marks the anniversary of the first major military action fought by Australian and New Zealand forces during the First World War.