Bacho Kiro cave, Show cave near Dryanovo, Bulgaria

Bacho Kiro is a cave system stretching about 3600 meters underground with passages running across multiple levels connected by natural galleries. The pathways move through different chambers and limestone formations that shape the space throughout.

The cave opened to recreational visitors in 1938 and was renamed in 1940 after Bacho Kiro, a teacher and revolutionary of the April Uprising. Excavations in the first hall, the Vestibule, yielded Middle and Late Palaeolithic tools and, in 2020, remains dated to about 47,000 years ago identified as Homo sapiens — the earliest known presence of our species in Europe. A 3 m bear skeleton was also found.

The cave was renamed in 1940 after Bacho Kiro, a teacher and leader of the April Uprising, two years after recreational visitors first entered. Inside, a low 60 by 40 cm corridor called "Purgatory" is said to be passable only by a righteous person. Four bat species, including the greater and lesser horseshoe bats, winter here from December to late March.

Of the 3,600 m of galleries, 700 m are fitted for visitors and lit by electric light since 1964. The entrance lies 300 m west of Dryanovo Monastery, in the Andaka canyon. Inside it is a constant 13 °C with 95% humidity, so bring a jacket. The low corridor called Chistilishteto measures 60 by 40 cm.

The temperature inside stays constant at about 13 degrees Celsius year-round, creating a steady environment throughout the seasons. Some of the rock formations are named after how they look, such as The Dwarf and The Sleeping Princess.