The official anniversary of Vimy Ridge, which featured four Canadian divisions fighting together as a unit for the first time to take the almost impossible ridge from German defenders is April 9, although the battle stretched on four days.
The area around the memorial was also lined with empty black combat boots, representing those who died.
It's the moment, they say, when Canada was born - or at least came of age as a country.
"Today, as we mark the 100 anniversary of the battle, we honour the soldiers who fought at Vimy".
Charles told thousands of Canadians gathered along with France's president Francois Hollande and other dignitaries that: "The long shadows of the thousands who fell here still touch us today". "We must never forget their service and sacrifice".
Today, the Canadian Medical Association (CMA), along with all Canadians, would like to acknowledge the courageous soldiers, and in particular, the physicians who contributed to the Battle of Vimy Ridge 100 years ago. Without freedom, there can be no peace.
"These ordinary and extraordinary men of the British dominion fought for the first time as citizens of one and the same country", Prime Minister Justin Trudeau said in French as he addressed the crowd.
The site became a piece of Canadian territory on French soil in 1922 and is featured on the $20 bill.
Prince Charles commended the "strength of character" of Canada's troops.
"In the early morning hours of April 9, 1917, after meticulous planning, Canadian soldiers stormed Vimy Ridge".
"However, victory came at an unbearably heavy cost".
"As Colonel-in-Chief, Captain General and Air Commodore-in-Chief of Canadian Armed Forces units, I have often borne witness to the professionalism and dedication, as well as the sense of equality, of respect, of perseverance, of sacrifice and of hope that infuses our military".
In 1936, as Canadians and many others around the world watched the Vimy monument's unveiling, retired brigadier-general Alexander Ross famously intoned that the battle had marked "the birth of a nation". "This was Canada at its best".
The Vimy Ridge commemorations were a time for Canadians and others to reflect on the First World War and the lessons it still holds a century later.
The ceremony honored and remembered Canadian soldiers who were killed or wounded during the battle in 1917.