Bacho Kiro Cave

Bacho Kiro Cave is a four-storey labyrinthine cave system 5 km west of Dryanovo, Bulgaria, located 300 m from the Dryanovo Monastery [1]. With a total length of 3,600 m, it features an underground river that carved galleries containing stalactite, stalagmite, and stalactone speleothems of great beauty [1]. The cave contains archaeological evidence of Initial Upper Palaeolithic Homo sapiens occupation dating to approximately 46,000–43,000 years before present, making it the earliest directly dated site of Upper Palaeolithic modern humans in Europe [2][3]. Of the cave, 700 m are open to the public with electrical lighting installed in 1964 [1].