Australia and New Zealand marked the 100th anniversary of the outbreak of World War I today, with Prime Ministers Tony Abbott and John Key calling it a conflict that shaped their nations.
Some 61,000 Australians and more than 18,000 New Zealanders died in the war, an event Abbott said was "the most cataclysmic event in human history".
"World War I arguably gave rise to communism, to Nazism, to World War II and the Cold War," he said at a wreath laying ceremony in Canberra one of several commemorations taking place across Australia.
"The events of a hundred years ago still reverberate around our world today and it had a shattering impact on the young Commonwealth of Australia.
"From a population of under five million people, more than 400,000 enlisted, more than 300,000 served overseas, more than 150,000 were wounded and more than 60,000 were killed.
"This cauldron shaped our nation. Even now, these events shape our nation.
"For us at least, World War I was not a war of conquest, it was a war of freedom. It was a war for our allies, for our values," he added.
The bloody conflict, which officially began on August 4 when Britain declared war on Germany after its invasion of Belgium, remains the most costly in terms of deaths and casualties that Australia has been involved in.
In New Zealand, the military staged a 100-gun salute on the Wellington waterfront to mark the centenary, with 105mm howitzers booming out the commemoration over eight minutes.
Key told a parliament ceremony that the start of the war had a profound effect on New Zealand, which had only been declared an independent dominion from Britain seven years earlier.
"The first World War changed how New Zealanders viewed ourselves and how other countries view us," he said. "It laid the foundations for the country that we have become today.
"For New Zealand... The centenary is an opportunity to recall the part paid by our forces, to honour the service and sacrifice of our countrymen," he added.
Key made special note of the bond it had with Australia during the war, when the heavy losses suffered by Australia and New Zealand Army Corps troops in the 1915 Gallipoli campaign helped forge the identities of what were both fledgling nations at the time.
The four-year conflict that became known as the Great War left some 10 million dead and 20 million injured on the battlefields. Millions more perished under occupation through disease, hunger or deportation.
