It’s not a real mountain and it’s neither alien made. It’s the entrance to a universe of discoveries: the Austrian - Swarovski Museum (Kristallwelten or Crystal World). It is a crystal theme park at Wattens (near Innsbruck, Tyrol, Austria). The Swarovski Crystal Worlds opened in 1995. There are 14 subterranean chambers devoted to diverse artistic interpretations of crystal. If you cannot visit the museum, do a virtual tour at http://kristallwelten.swarovski.com
Photo credit Flickr user 'htsu'.