France President Emmanuel Macron with German Chancellor Angela Merkel (Picture: PA).
US President Donald Trump joined French President Emmanuel Macron and other world leaders as they gathered in the French capital to mark a century after guns fell silent in a global war that killed millions.
Fighter jets passed overhead as the leaders walked to the ceremony at the Arc de Triomphe.
5 million men from 30 countries fought in the First World War and more than 9 million fighting men were killed, one third of them through disease.
At least 750,000 soldiers killed were British and over 188,000 were from the British colonies.
In the UK, millions of people across the country also fell silent to mark the centenary.
A series of events took place up and down the UK - the biggest being at the Cenotaph in Whitehall, London.
The Prince of Wales lead the nation in honouring the country's war dead during the national service of remembrance.
The Queen asked Prince Charles to lay a wreath at the Cenotaph in Whitehall on her behalf - the second successive year he has performed the duty.
During the Cenotaph service, the Queen watched on from the balcony of the Foreign and Commonwealth Office building.
After Prince Charles laid a wreath on behalf of the Queen, other floral tributes were left by members of the royal family, senior figures from the government, including Prime Minister Theresa May, and opposition party leaders and other figures from national life.
Armistice Day marks the day the First World War ended on the 11th hour, of the 11th day, of the 11th month in 1918.
It is not to be confused with Remembrance Sunday, which falls on the second Sunday in November every year.
This year, 100 years on since the Great War ended, Remembrance Sunday and Armistice Day have fallen on the same day.
Also, for the first time, a German leader laid a wreath at the Cenotaph.
President Frank-Walter Steinmeier performed the duty on behalf of his nation in an historic act of reconciliation between the two countries.