One of the most spectacular natural phenomena in Bulgaria - Chudnite Mostove (Wonderful Bridges), is 16 km away from the turn at road II-86. This monument is located in a centuries-old spruce forest at 1,450 m a.s.l., at the upper section of the river Aydarsko Dere (Dalbok dol area). Wonderful Bridges are a natural rock ‘bridges’ formed for the space of a thousand years.

Specialists believe that once here was a deep karst cave formed by a river and probably a strong earthquake caused the collapse of the ceiling, than the stormy waters of the river carried the rocks away and creating the two natural marble bridges. The largest one of them is 96 m long and 70 m high. The vault rises 45 m above the river, and the marble rock is 12-15 m wide. Within its walls, there are two interconnected caves, as as well as numerous karst cavities where birds and bats find refuge. The second bridge is about 100 m down the ravine and is 50 m high.

The area around the bridges is secured by railings and stone steps have been carved to facilitate the access.