Devil's Holes are a rock ridge and system of karst formations located in the canyon of the Proboynitza River — a tributary of the Iskar. The area is located in the Vratsa Balkan and is distinguished by its characteristic rocky structure.

The rock ridge is about a kilometer long and includes numerous cavities, passages and cave formations. A path passes under it, which allows viewing the formations up close.

The place is less visited and offers a wilder and more authentic experience, suitable for nature lovers and more adventurous routes.