This silly American had a lot of learning to do too, BetaRose.
Canada Day is the celebration of Canada's Confederation.
From the National Library of Canada:
(Confederation is) the coming together of the colonies in British North America. Three colonies were made into four provinces. These were Ontario, Quebec, Nova Scotia and New Brunswick. They became the Dominion of Canada on July 1, 1867. The other provinces and territories joined later.
From the Canadian Heritage Website:
http://www.pch.gc.ca/special/canada/11/canada_e.cfm
Canada Day is an opportunity to gather in our communities, from sea to sea, and to proudly celebrate all we have in common. It is an opportunity to celebrate our achievements, which were born in the audacious vision and shared values of our ancestors, and which are voiced in nearly all of the languages of the world through the contribution of new Canadians.
Canada Day is a time to celebrate the heritage passed down to us through the works of our authors, poets, artists and performers. It is a time to rejoice in the discoveries of our scientific researchers, in the success of our entrepreneurs, and to commemorate our history — a history in which each new chapter reveals itself to be more touching, more fascinating than the last.
As we look ahead, we have every reason to face the future with confidence and enthusiasm.