Ultra trail Stara planina, at the beginning of June on Stara planina. Organized by the Sky Running Association of Serbia, and under the auspices of the Ministry of Youth and Tourism, celestial runners compete at 2000m above sea level in a kind of endurance race. The organizer changes the trails and distances every year, so that competitors can get to know as much as possible 114,000 ha of the landscape of untouched nature of Stara Planina.
- Time of event: June
- Organizer: Sky Running Association