Now a popular sight crowded with tourists, this open-air museum was once a place of solitude and prayer. Two monasteries hollowed in the rock demonstrate the austere environment in which the monastic communities of the 11C developed and visiting the cave churches here is a moving experience. The churches include the Church of the Sandals, which is open to the sky; the Church of St Basil, the narthex of which is hollowed out with tombs; the Church of the Apple, with its polychrome paintings; the Church of the Snake; and the Dark Church. The most enigmatic of the churches, the Church of St Barbara, is adorned with naive frescoes, the meaning of which is still debated by specialists.