French President Emmanuel Macron has urged dozens of world leaders marking a century since the end of World War I to come together for a joint "fight for peace".
"Let us build our hopes rather than playing our fears against each other," he told leaders, including the presidents of the United States and Russia on Sunday.
France, the epicentre of the first global conflict, is hosting the main international commemoration with about 70 world leaders gathering at the Arc de Triomphe in Paris at 10:00 GMT to mark the milestone moment.
"The traces of this war will never be wiped away. Neither in France, nor in Europe the Middle East, nor all over the world," Macron said.
"Let us remember, let us not forget. Because the memory of these sacrifices makes us worthy of those who fought and died so that we can be free. So let us remember," he said.
"Let us not give up the ideals, the principles and the patriotism of those who fought."
Soldier testimonies
Testimonies written by soldiers on November 11, 1918, as the ceasefire took hold, were to be read at the event, which will also feature warnings about the modern-day danger of nationalism.
Far-right nationalist politicians from Brazil to Italy to Austria were also present at the event.
The first world war erupted in 1914 after a teenage Bosnian Serb assassinated Archduke Franz Ferdinand, the heir to the Austro-Hungarian throne, igniting a conflict that was contemporaneously described as "the war to end all wars".
In the four years of fighting, remembered for brutal trench warfare and the first use of gas as a weapon, France, the British empire, Russia and the US had the main armies opposing a German-led coalition that also included the Austro-Hungarian and Ottoman empires.
More than 70 million military personnel were mobilised and an estimated 10 million lost their lives.
