About 1km north of the centre, overlooking the river, the marvellously intact Baba Vida Museum-Fortress is largely a 17th-century Turkish upgrade of 10th-century Bulgarian fortifications, which in turn were built upon the ruins of the 3rd-century Roman fort of Bononia. There's little to see inside, but it's an atmospheric place. Watch out for uncovered holes and the sheer drops from the top.
