The Holy Trinity Kamenno-Brodskiy Monastery is one of the most beautiful and visited monasteries in the Lower Volga region. The monastery is known for its miraculous icon of the God's Mother "Joy of All Who Sorrow" and the caves which take the second place after the Mount Athos caves for their holiness. According to the legends, many of which have scientific proof, the caves have the most mysterious subterranean labyrinth in the world. Behind spacious tunnels, where monks spend the rest of their lives, behind the amazing subterranean chapel there are gaps which lead to mysterious uncertainty. The galleries diverge in different directions for more than 300 kilometres. But the most astonishing thing is that the platform at a depth of fifty metres, where tourists can get, is only the first level of the caves. The subterranean labyrinth goes further on the second and even third levels.