24 Famous places to visit before they disappear

Pravcicka Brana, Czech Republic

Located in northwestern Czech Republic, the Pravcicka Brana is the largest natural sandstone arch in Europe. During the time when this unique rock formation was accessible to tourists, the upper part of the arch eroded by 80 centimeters (32 inches). Since 1982, visitors have not been allowed on the arch but the process of disintegration continues and geologists suggest the arch might collapse within decades.