Thousands of students packed Toronto's Air Canada Centre Thursday for the annual "We Day," a global youth movement that celebrates a yearlong commitment to volunteering.

Started by Free the Children founders, brothers Craig and Marc Kielburger, the first We Day event was held in Toronto in 2007. Approximately 8,000 youth took part that year.

Since then, the one-day party has grown to include more than a dozen cities, including Montreal, Vancouver and Seattle. A number of big-name celebrities have also lent their star-power to the event.

Guests at this year's star-studded party in Toronto include pop singer Joe Jonas, Canadian rapper Kardinall Offishall, and retired Canadian astronaut Chris Hadfield. Many of the attendees posted photographs of the guests this year as they shared inspiring messages to continue volunteering in the future.

 
Post by Joe Jonas France.

To attend a We Day event, students don’t buy tickets, but instead earn their way to the "party" by taking part in a year-long initiative called the We Act. The program offers students and teachers with free educational materials to create student-led campaigns that support local and global causes.

Many of the attending schools at this year's event shared photos of the party on social media.

Since 2007, We Day has helped raised approximately $37,000,000 for hundreds of organizations.