Sliven is situated at the foot of the unique rock massif 'Sinite Kamani' (The Blue Stones), very close to mineral springs. The town is famous for its clean fresh air, clean water sources, mild winter and cool summer. Sliven is the only Bulgarian town that has never changed its Slavonic name, though it is one of the oldest settlements in Europe. Here lived Thracians, Romans, Slavs, and Ancient Greeks. The first Roman settlement on this place - Tuida ( The 3rd century BC) was a famous trade centre. Sliven was mentioned as a big town for the first time in 1153 by the Arab traveller Idrisi.