Smolinskaya cave near Kamensk-Uralsky in the Middle Urals with underground halls and grottoes is of karst origin, it is inconspicuous from the outside, but the length of the passages is 890 meters. In the XVIII-XIX centuries there was an underground monastery and chapels of the Old Believers. Now the cave is inhabited only by bats, but they, hung on the ceilings for hibernation, cannot be photographed with a flash, awakened at the wrong time, they will die from cold and starvation. The air is humid, from the breath of people, suspended droplets are formed in it, which are visible only with a flash, they also glow on the ceilings.→