Thursday marks 50 years since the opening of Three Rivers Stadium in Pittsburgh.The former home of the Pirates and Steelers opened on July 16, 1970, with the Pirates hosting the Cincinnati Reds.Many major sports moments happened at Three Rivers Stadium, including the Immaculate Reception in 1972.The Steelers and Pirates played their final games at Three Rivers Stadium in 2000.The stadium was imploded in 2001.The Pirates now play at PNC Park and the Steelers at Heinz Field.