A design by architect Richard (Su Min) Lee was chosen (and used again for the Lewiston-Queenston Bridge, approximately downriver). The bridge's Rainbow Tower and Canadian plaza are the work of Canadian architect William Lyon Somerville. King George VI and Queen Elizabeth, during their visit to Niagara Falls as part of the 1939 royal tour of Canada, dedicated the site of the Rainbow Bridge; a monument was erected to commemorate the occasion. Construction began in May 1940. The bridge officially opened on November 1, 1941.