Each year, millions of so-called “dark tourists” flock to these sites to witness what remains of their tragic pasts http://on.natgeo.com/2yVW396

Each year, millions of so-called “dark tourists” flock to these sites to witness what remains of their tragic pasts http://on.natgeo.com/2yVW396 

https://twitter.com/NatGeoTravel/status/924818159667957762