April 25 is a special day on the Australian and New Zealand calendar - it commemorates ANZAC Day. 

The day is used to remember all Australians and New Zealanders killed in military operations.

What does ANZAC stand for?

ANZAC stands for Australian and New Zealand Army Corps.

The name dates back to April 25, 1915, when the first ANZACs formed part of the Allied expedition that set out to capture the Gallipoli peninsula during World War I.

The Australian Army website said: "These became known as Anzacs and the pride they took in that name continues to this day."

What is ANZAC Day?

Anzac Day falls on April 25 each year and has done since 1916.

Describing the events behind ANZAC Day, the Australian Army website said: "On the morning of April 25, 1915, the Anzacs set out to capture the Gallipoli peninsula in order to open the Dardanelles to the Allied navies.

"The objective was to capture Constantinople (now Istanbul in Turkey), the capital of the Ottoman Empire, and an ally of Germany. 

"The Anzacs landed on Gallipoli and met fierce resistance from the Ottoman Turkish defenders."

Their plan to knock Turkey out of the war became a stalemate, with the campaign dragging on for eight months costing the lives of around 141,000 allied personnel including 8,000 Australians.

At the end of 1915, the allied forces were evacuated. Both sides suffered heavy casualties and endured great hardships.

The Australian Army added: "News of the landing on Gallipoli and the events that followed had a profound impact on Australians at home.

"The 25th of April soon became the day on which Australians remember the sacrifice of those who had died in the war.

"The Anzacs were courageous and although the Gallipoli campaign failed in its military objectives, the Australian and New Zealand actions during the campaign left us all a powerful legacy."

What happens on ANZAC Day? 

Commemorative services are held at dawn on ANZAC Day – the time of the original landing on Gallipoli took place - all over the world including in the UK.

Later in the day, ex-servicemen and women meet to take part in marches through the major cities and in many smaller centres.