THE ROCK Boulderhalle Karlsruhe on Clmb House. Venue in Erlachseeweg 1 (Oberwaldstadion), 76227 Karlsruhe-Durlach, Germany, Germany. THE ROCK Boulderhalle in Karlsruhe-Durlach is the city's oldest bouldering gym, a spacious hall known for classic lines and powerful overhangs. It has a Moon...