Kyustendil is a city and a municipality in southwestern Bulgaria and the city is located on the Banska River near the border with North Macedonia and Serbia. Kyustendil looks back on a long history. The Thracians had a settlement here, which was called Pautalia in Roman times. The city has its current name since the Ottoman Turks called it Küstendil, after Constantine Dragas, the monarch who held sway here in the 14th century.

Kyustendil features many historical sites that were built during the long existence of the city. One of them is the fortress of Hisarluk, which was built in the 4th century after frequent raids by barbarian tribes. It was rebuilt by the Byzantine emperor Justinian I between 527 and 565, and it was used until the 15th century. Other site are the Roman Thermae Complex, the Pyrgos Tower, the Church of the Assumption, the Ahmed Bay Mosque, and the Turkish Baths.