The stunning gorge of Jerma river disparts the limestone massifs of the Greben Mt. and Vlaška Mt. It is situated in far southeastern part of country along Bulgarian border. Jerma represents unique complex of valleys and limestone gorges with vertical cliffs more than 700 m tall, with numerous caves, pits, sinkholes and pebble stones. The limestone massif called Asenovo Kale 1032 m high, dominates over entire area. The highest point of area is peak Ruj (1704 m) on Ruj Mt. In total six small villages are situated inside IBA which divided by three municipalities (Pirot, Babušnica and Dimitrovgrad).