Here's one explanation:
Toronto, Ontario
Toronto is the business center of Canada. Financial services, high technology, and insurance companies top the list of businesses represented there. Toronto is home to more top-ranked international companies than any other Canadian city. It is true to its name, which is a Huron Indian word for "place of meeting." Bay Street is Toronto's Wall Street, and it is as controversial outside the city as Wall Street is outside New York.
It is the most ethnically diverse city in the Western Hemisphere, according to the United Nations. The city sparkles with life -- indeed, some maintain that it has become as sophisticated as Montreal. Its center remains vibrant and still retains good residential neighborhoods.
For most of its history it was considered by some to be a poor cousin to Montreal. Toronto became Canada's most populous city in 1977 and in the process seems to have gained in confidence. Having changed dramatically in the past generation, Toronto used to be referred to as "Hog Town." It was notorious for indifferent service in restaurants and stringent blue laws, and remaining shuttered on Sundays. This staid, if safe, atmosphere also earned Toronto the nickname "Toronto the good." Without sacrificing its safety and comfort, Toronto has evolved into a vital, interesting place. Credit for the metamorphosis must be given to the waves of immigrants who poured into the city from all over the world after World War II, bringing their customs with them.
http://globalgateway.monster.ca/articles/cities.asp