Royal Alexandra Theatre
Constructed in 1906-1907, this theatre is an intimate but lavish version of the traditional 19th century theatre, with two balconies as well as side boxes. John M. Lyle (1872-1945), one of Canada's most distinguished architects of the 20th century, designed the Royal Alexandra Theatre following the Beaux-Arts style, thus providing an elegant setting for Toronto's sophisticated theatrical and musical events. Since its rescue and rejuvenation by Ed Mirvish in 1963, when it was to be demolished for a parking lot, this theatre again plays a central role in the social and cultural life of the city.
Plaque via Alan L. Brown's site Toronto Plaques. Full page here.