Fans in sold out Three Rivers Stadium cheer St. Louis Cardinals Mark McGwire's first inning home run, his 52nd of the season, against the Pirates in Pittsburgh in this Aug. 22, 1998 photo. Three Rivers Stadium is celebrating its 30th birthday this weekend. There won't be a 31st, and not many players and fans are disappointed. A supposedly futuristic, early-for-its-kind sports arena when it opened on July 16, 1970, Three Rivers helped usher in a brave if not exactly well-conceived new world to pro sports.(AP Photo/Gary Tramontina)