The Cansiglio is a karst area characterized by subsidence of the ground (depressions) these are by all means real chasms and can be dangerous. Among the chasms on the race ground there is the infamous “Bus de la Lum” , a complex of caves 180 m deep over. In ancient times, legend say this complex was a destination where witches ate children who got lost in the woods (hopefully, orienteers do not get lost!) . More recently, this area has become notorious for some terrible events that occurred during World War II as they were used for mass graves. Other chasms less famous but much deeper are the Bus de la Gentian (-588m) and the Chasm of Col della Rizza (-800m), both just outside the race grounds.

The organization will mark any dangerous spot in the mapped cards  and fence the most dangerous holes that already do not have protections. The race course however  will be designed to ensure that athletes do not pass through these dangerous zones. It is recommended not to enter fenced areas for any reason and to pay the utmost attention in any case.