The Overgrown, Disused Railway That Still Runs Around Paris

Paris has a lot of history embedded in its sprawling urban grid, which has seen thousands of years of structural change. But even though space is at a premium, there are still spots that have evaded development and slowly drifted into obscurity.
Like the Chemin de fer de Petite Ceinture (or Little Belt Railway), a 20 mile stretch of disused tracks along the Parisian perimeter. The railway was constructed in 1852; at that time, the major stations were owned by different companies, and this was a way to streamline connections through a path that tunneled, bridged, and cut a deep-walled passage within the crowded streets.