 By 1951, Montreal's population had surpassed one million. However, Toronto's growth had begun challenging Montreal's status as the economic capital of Canada. Indeed, the volume of stocks traded at the Toronto Stock Exchange had already surpassed that traded at the Montreal Stock Exchange in the 1940s. The Saint Lawrence Seaway opened in 1959, allowing vessels to bypass Montreal. In time this development led to the end of the city's economic dominance as businesses moved to other areas. During the 1960s there was continued growth, including the World's Fair known as Expo 67, and the construction of Canada's tallest skyscrapers, new expressways and the subway system known as the Montreal Metro.
