By Tanner Garrity There are some startling photos online of old Olympic stadiums and villages that have fallen into disuse and disarray over the decades. It’s a familiar, unfortunate story for both former summer and winter host cities: billions are spent on elaborate new structures, the planet watches them on TV for all of two weeks and that’s that. Mere years later, vegetation sprouting between bleachers, the once-proud sites can look downright apocalyptic. One city, though, treated the Olympics as an opportunity for urban regeneration. When Barcelona hosted the 1992 Games, the city neglected…