The one-year countdown for the 2015 Toronto Pan Am and Parapan Am Games started on Thursday.

To drum up some excitement for the multi-sport event, organizers of the Pan Am Games will host a two-day, free party at Toronto's Nathan Phillips Square on Friday and Saturday.

The event will feature appearances by world-class athletes, the unveiling of an official 2015 Pan Am Games countdown clock, live music and fireworks.

Other Pan Am host communities in the Greater Toronto Area, including Ajax, Burlington, Markham and Mississauga, will also host their own festivities.

In advance of the official countdown party and the Pan Am Games, here are five things to know about the 2015 sporting event:

When:

Pan Am Games: July 10 to July 26, 2015

Parapan Am Games: August 7 to August 15, 2015

Sports:

The Pan Am Games features 36 sports. They include all the usual Olympic ones, and some Pan Am-only events, such as handball, roller figure skating and wakeboarding.

The Parapan Am Games features 15 sports, including boccia, goalball and wheelchair tennis.

History:

The first Pan Am Games were held in Buenos Aires, Argentina in 1951. Approximately 2,500 athletes from 22 countries participated in the inaugural games, which are now held every four years. Toronto will be the 17th Pan Am Games host. Approximately 7,600 athletes from more than 40 countries are expected to participate next year.

The first Parapan Am Games were held in Mexico City in 1999. They are also hosted every four years.

Venues:

The Pan Am Games will be hosted at more than 30 locations across the city and the GTA, including York, Durham and Peel regions. They include 10 new facilities and 15 upgraded ones.

Volunteering:

To bring the Pan Am Games to life, organizers will be relying on more than 20,000 volunteers. To learn how you can help out, visit the Pan Am Games website.