Each year millions of people trickle through the shadowy halls of decommissioned prisons around the world to learn their grim histories https://on.natgeo.com/2GoVmtk

Each year millions of people trickle through the shadowy halls of decommissioned prisons around the world to learn their grim histories https://on.natgeo.com/2GoVmtk 

https://twitter.com/NatGeoTravel/status/980172958936260613