S-56 is a pre-war Russian submarine that has been preserved as a museum a short walk from downtown Vladivostok. It is well-preserved and well-presented, although much of the propulsion machinery is no longer present.
Nearby (across the road) the old naval auxiliary Krasny Vympel is moored and also open to visitors.
Links and References:
Memorial ship "Krasnyy Vympel" ("Red pennant")
George, A, 2014, Vladivostok Treasures: Krasny Vympel & Submarine S56, Warship World, 14 (1), pp25-26.