At the beginning was the original O-SEE-CHALLENGE and later on was the XTERRA CHALLENGE added to the event. The original O-SEE-CHALLENGE started in 2000 and was a mix of a triathlon and an adventure race. There aren't any compelling contest rules. The motto is: join in, arrive and have fun. This principle is still inhibited in the ORIGINAL TRAIL, the O-SEE-CLASSIC. Who ever starts here wants still compete and having fun in the same time.