Little is known about this bizarre rock monastery; the caves were first inhabited by 11th-century hermits, but what remains today was created during the 13th and 14th centuries, including some remarkable frescoes. A signposted path (600m) leads to the three-level catacombs, accessed by stairways. There's also a small but interesting museum on the history of Bulgarian archaeology.
To walk to the monastery from Golden Sands, head up the road past the post office, cross the main Varna–Albena road, and follow the signs to ‘Kloster Aladja’ and the markings along the obvious trail. The walk takes an hour one way, and wends its way through a wonderful, shady forest, part of the 1320-hectare Golden Sands Nature Park.