The residents of Sevastopol and the Baidar Valley know this place under the name "Alsu". The old Tatar name is translated as "red water". Whether it is connected with the geological features of the place, or with an old legend - no one remembers. However, the history of the name was the least of the worries of those who worked at a top secret construction site. They listed it under their own name: “object 221”. The construction of the underground Command Post of the Black Sea Fleet in Alsu began in 1977. It was planned to house the headquarters of the Black Sea Fleet and maintenance personnel. There is information that in the event of a war, a high-ranking leadership should have been placed here, resting in the dachas of the South Coast and in the vicinity of Sevastopol.
"Object 221" has four underground floors, two main entrances. The total area is 17.5 thousand square meters, this is the largest underground structure in the Crimea. The object under the 180-meter layer of rock is a network of tunnels, in which KAMAZ can easily pass. It has five levels and an upper platform for antenna equipment, the tunnels lead to a huge network of premises - it was planned to place all the services of the fleet headquarters in them.