On March 6 , 2009 , the city celebrated the 175th anniversary of its inception as the City of Toronto in 1834 . Toronto hosted the 4th G20 summit during June 26 – 27 , 2010 . This included the largest security operation in Canadian history . Following large-scale protests and rioting , law enforcement conducted the largest mass arrest ( more than a thousand people ) in Canadian history
4th G20 summit
2010 G20 Toronto summit
Toronto