Grevena area and especially the lush green Orliaka mountain slopes with black pine trees and robola vines are full of caves. The most famous are: The CAVE in Desketi (Aghia Paraskevi location) and the caves in Zakas area. Especially the latter route is amazing: From the edges of the village a cobbly road reaches the entrance of Portitsa gorge with the homonym stone bridge which dates back to 1743. The river gets narrower at the gorge’s entrance while an underground river splashes the rocks. In the corner of the right wall, invisible from the base of the rock, is Keli tis Kalogrias, a cave full of stalactites and stalagmites. Very close to it is Vaenaki. It is a cave with two openings among sharp rocks and water drips from its walls.