Montréal's Olympic Stadium is widely considered to be a white elephant. Built in the early 1970's for the 1976 Summer Olympics, it was wildly over budget and not even complete for the opening ceremonies. For a while, it was the home of the Montreal Expos (Major League Baseball) and the Montreal Alouettes of the Canadian Football League. Widely reviled by spectators as being cold, unfriendly, unwieldy and even dangerous (a 50-ton slab of concrete once fell off the side of the building, thankfully not crushing anyone), the teams either moved out of the stadium or out of town. Today it's used for special events where a capacity of 50,000 people is required. Otherwise, it sits pretty much empty most of the time.
Several studies were made to determine whether it should be demolished, but each study came back with the same conclusion: there is SO MUCH CONCRETE in this thing to haul away that it would be cheaper to continue operating the place for something like 50 years than it would be to demolish.