In over 80 countries May Day, or International Worker's Day is an official holiday celebrated by millions of people around the world. Organizers in cities across Canada have planned events that we've compiled for our readers below. Click on the links for more info.

But first...here's a brief look back at how it all started:

May Day began in the U.S. as a response to the abuse of state power -- as an international act of solidarity and camaraderie amongst working people everywhere.

From its inception 40 years ago Earth Day has been a student-centric event.

Not surprisingly, Earth Day's origins can be traced to a single instance of environmental devastation when Wisconsin Senator Gaylord Nelson was touring the Santa Barbara coastline assessing the damage caused by an oil spill.

Nelson had long been contemplating a way in which to infuse environmental issues into the political discourse in Washington D.C. During a flight from Santa Barbara to San Francisco, Nelson was reading about the effectiveness of student led anti-war teach-ins on college campuses across the U.S. and concluded that the same format could prove just as successful for environmental issues: