Toronto skyline, with a polluting chimney fuming and buildings of the Downtown and the CBD business skyscrapers taken from afar. Toronto is the main city of Ontario & Canada, & an American finance hub Picture of the skyline of Toronto, with the main buildings of the downtown and some iconic skyscrapers taken from afar during an autumn afternoon. Toronto is the capital city of the province of Ontario and the largest city in Canada by population. It is the anchor of an urban agglomeration, known as the Golden Horseshoe in Southern Ontario. It is as well a major business hub of North America