1934 - Liberals come to power led by Hepburn. 1949 - Leslie Frost becomes Conservative Premier. St. Lawrence River hydro and Seaway developments. Ontario Hydro also moves towards nuclear energy. 1954 - Metropolitan Toronto established.
Subway system opens in Toronto.
Over one-fifth of Ontario's population are immigrants. 1962 - First nuclear plant opens at Rolphton. 1976 - Completion of the C.N. Tower in Toronto. 1989 - Completion of the Skydome. 1990s - Economic recession.