Blagaj Fortress in City of Mostar

You're standing at Blagaj Fortress, which locals also call Stjepan-grad. It sits on top of a steep karst hill, some 266 metres above the spring of the river Buna. Take a careful look over the edge. On the south, west and north sides the cliffs drop away almost vertically. The only way in was from the east, and that's exactly where the wall is thickest.