The incomplete Submarine Shelter Pavlovskoe, formerly known as “secret object no.6,” stands deserted on the coast of Peter the Great Bay in the Primorye Region of Russia. The concrete structure with its semi-circular arches harks back to the times of the Cold War when the Soviet Union and the USA were engaged in a nuclear arms race.

It was intended as a submarine base for the Pacific Fleet and is situated 19 kilometers from Nahodka, one of the port towns of the region. It is located within a base of both the Ministry of Defence and the Pacific Fleet.

Pavlovskoe was designed to provide shelter for Pacific Fleet submarines in the event of a nuclear attack. Construction allegedly began in the 1960s, although some sources claim dates as late as 1977. It is impossible to confirm the starting date with any certainty because of the secrecy surrounding the operation.

Construction work started to slow down in the 1980s due to a lack of funds and it was finally brought to a halt when the Soviet Union collapsed. A significant factor in the discontinuation of construction efforts was START I, the first of the Strategic Arms Reduction Treaties between the Soviet Union and the USA.

START I was signed on July 31st, 1991, just four months before the Soviet Union collapsed. Its aim was to achieve the reduction and limitation of strategic offensive arms.

The Soviets were obliged to close the entrances of some of their underground structures to any maritime objects, as well as to stop the building of any such structures. This affected Pavlovskoe, and the shelter remained unfinished even though most of the building work had already been completed.

The submarine shelter consists of two main tunnels connected by a network of secondary tunnels, built on three different levels. It was an impressive feat of engineering as the network of tunnels was carved into the cliff rock.

The sheer size of the main tunnels is breathtaking. According to data collected by KFSS, a local urban explorers community, the first tunnel is 21 yards wide and at least 490 yards long. The concrete is about 2 yards thick. At its highest point, it sits 11-13 yards above water level. It is this tunnel that the submarines were supposed to pilot into, half-submerged in water, in the event of a nuclear emergency.

The second tunnel leads into the main hall, which was a space for the main living and working quarters. The main hall is 246 yards long, 9 yards wide, and approximately 12 meters high. In places, stalactite-like icicles hang from the ceiling.

It is hard to tell exactly how large the shelter is as many tunnels have been flooded or blocked off. There are at least 8 entrances and at least 2 ventilation shafts, but there could be more.

Pavlovskoe is located within the territory of Pavlovsk – an operational submarine base – so no trespassers are allowed in the area. The territory also evidently has radiation sources as the radiation count is above normal, but the causes are unknown, at least to the public.

Photos and information source: KFSS, a group of urban explorers who document abandoned structures and buildings of the Russian Far East.