Analysis by H I Sutton, writing in NavalNews.com, suggests that the Russian Navy is re-establishing a base at Balaklava, a small inlet 5 miles south of Sevastopol that was the site of a major naval base during the Cold War. In the 1950s the Soviets dug a submarine tunnel into the mountain on the west side.
The submarine tunnels fell into disuse after the collapse of the USSR and the base was inherited by the newly formed Ukrainian Navy. Although some small warships were present from time to time, the base was largely forgotten. And, after years of abandonment, the submarine tunnels were turned into a museum. An old Romeo class submarine, S-49, was added in 2021.