The 14th-century fortress Baba Vida is the best-preserved medieval Bulgarian fortress. It is located in the northern part of the city of Vidin at the bank of the Danube. During a 45-minute guided walk you see the large, well-preserved square facility boasting several massive gates. It is cornered by four square towers. A one-hour bus ride brings you to Belogradschik where you can admire the only rock city of the world. You then visit the near by fortress with its massive walls and crenels that surround the building in three stages like terraces. The high walls enclose an irregular pentagon with two separate courtyards behind which you can find the ruins of a small castle. It actually dates back to Roman times.