ANZAC Day

Anzac Day is a day that happens once a year in Australia and New Zealand. It is celebrated by both countries on 25th April every year. It was to commemorate (honour) the members of the Australian and New Zealand Army Corps (ANZAC) who fought at Gallipoli in the Ottoman Empire during World War I. Now though, it celebrates all "who served and died in all wars, conflicts, and peacekeeping operations" and "the contribution and suffering of all those who have served." 
Anzac Day is also observed in the Cook Islands, Niue, Pitcairn, and Tonga. In the past, it was a national holiday in Papua New Guinea or Samoa.