Ultramaraton Zapomenuté hory in 2023, a running event organized in Uhelná (Czech) on 21 October. During the 3 races were held event. Course 75k (⨦ 74.5 km / + 3 250 m) in class RMT5 with average terrain slope 4% (G4). Course 45k (⨦ 47 km / + 2 050 m) in class RMT3 with average terrain slope 4% (G4). Course 25k (⨦ 26.5 km / + 1 000 m) in class RMT2 with average terrain slope 4% (G4).