Faslane nuclear submarine base is home to the United Kingdomís strategic nuclear deterrent and the headquarters of the Royal Navy in Scotland.
RNAD Coulport, eight miles from Faslane, is responsible for the storage, processing, maintenance and issue of the Trident Weapon System and the ammunitioning task for all submarine embarked weapons.
Lorient housed a German submarine base during World War II; although the city was heavily damaged by Allied bombing raids, the base survived through the end of the war. As they could not destroy the base itself, the Allies decided to bomb the city, on purpose, to cut the supplying of the U-Boats. Without gasoline, food, or water it became impossible for these submarines to return to the Atlanti...
New Chinese bases, some under the mountains, where new nuclear submarines can dock and be hidden from satellite imagery. There are several tunnels leading into the mountain and huge piers at which to dock warships.
Submarine in Venice.
"Arsenale Militare di Venezia"
Additional info from McMaster_de:
It's a SSK (submarine-submarine killer) of the Toti Class. The Enrico Dandolo was finished on 16th December 1967 and disarmed in July 1999.