Canada Day formerly Dominion Day is the national day of Canada, a federal statutory holiday celebrating the anniversary of the July 1, 1867, enactment of the British North America Act (today called the Constitution Act, 1867), which united three British colonies into a single country, called Canada, within the British Empire. Originally called Dominion Day, the name was changed in 1982, the year that Canada gained full independence from the United Kingdom. Canada Day observances take place throughout Canada as well as internationally.
That's the technical explanation, but Canada Day also means fireworks and the year's biggest national party. The Canada Day holiday is akin to the U.S. July 4th celebration but on a more Canadian scale
HAPPY CANADA DAY