With over 25 years of history, the O-SEE Challenge is one of the longest-running events on the XTERRA circuit. This three-day festival brings together elite, age-group, and youth athletes from around the world to take on the battle-tested trails of Zittau at Germany’s most renowned off-road triathlon.
In 2026, the XTERRA European Trail Run Championship joins the O-SEE Trail lineup, bringing a global community of runners together beneath the medieval ruins of the Zittau Mountains. While European titles and World Championship slots are decided over the 25K and 50K tracks, Discovery races welcome beginners and kids, and two Endurance races take runners deep into the 75K and 100K loops that cross the border territory.