The Mane Garrincha National Stadium in Brazil—demolished and rebuilt for the 2014 World Cup—is now being used as a parking lot for buses.
According to Lourdes Garcia-Navarro of NPR.org, the $900 million stadium in the nation's capital, Brasilia, now serves as a parking lot, while a number of other stadiums built for the World Cup are similarly unused (h/t Vox.com).
The Arena Pantanal in Cuiaba, which cost $215 million to build, has hit the headlines repeatedly of late, first for being closed down due to faulty construction and then for homeless people squatting in its unused locker rooms.