The Chemin de fer de Petite Ceinture (French for “little belt railway”) was a 32 km railway that encirled Paris, connecting all the major railway stations within fortified walls during the Industrial Revolution. In service from 1852 to 1934, the line has now been partially abandoned for 80 years. Several developers and local officials have recently set their sights on the vast swath of unused land, tunnels, and stations as an opportunity for new development. However, some railway enthusiasts and related organizations want the tracks and stations to be preserved indefinitely as part of the cities’ heritage. Others want to turn areas of de Petite Ceinture into parkways similar to the nearby Promenade plantée, a 4.7 km park built on an elevated train track in 1988 that later inspired New York’s famous High Line. As part of his project “By the Silent Line,” photographer Pierre Folk has been working since 2011 to photograph the 160-year-old railway’s last remnants before any final decisions are made. He stalks the tracks at all times of the year, often returning to the same locations to document nature’s slow reclamation as rusted tracks and crumbling tunnels are swallowed by trees, vines, and grass. This is just a small selection of Folk’s work, you can see many more photos right here.