Since February 2013, groups of friends, colleagues, families and students have been voluntarily locked up underground in Berne to experience an adventure that is unique in Switzerland: Completely on their own, the group must explore spaces, find hiding places and secret doors and find the meaning behind mysterious objects, devices and signs to find the escape route and finally regain freedom. Similar situations are known from films or computer games, but here the participants themselves are the main actors, and you don't deal with virtual objects on a screen, but with real objects.
