Founded by Georgians in the 10th century, this castle ruin retains a fairly well-preserved watch tower and curtain wall guarding a river crossing below Şavşat town, 3km towards Artvin beside the main road. Climb 202 steps to reach the information board and the (often closed) gate.
If it's open, you can see the fruits of an 11-year archaeological investigation, with identified features including a wine cellar, a pharmacy and an Ottoman hamam. The site was once the ruling seat of Shavsheti, one of the princedoms within the Georgian kingdom of Tao-Klarjeti.