Proval Lake and the cave are the literary monuments on the map of Pyatigorsk. Its popularity is due to the Soviet writers Ilf and Petrov and their novel «Twelve Chairs». When the main hero of the novel Ostap Bender ran out of money, he with the inherent resourcefulness began selling tickets to the Proval. This episode is reminiscent of the bronze figure of Ostap Bender at the entrance to the grotto. Bronze lions accompany him.
The lake was called Proval (breakdown) by Academician Johann Güldenstädt, who first described it in 1773. The cave near the lake was formed as a result of the earthquake and originally had a shape of a funnel. The tunnel for access to the Proval Lake was breached in 1858. The water in the lake bright blue with the smell of sulfur and warm from 26 to 42 ° C, is considered to be curative, but one cannot swim in it: the observation deck has a grating. The icon of the Great Martyr and Healer Panteleimon is opposite the niche. Tourists go to the cave and lake through a small backlit tunnel which leads to the goal.