the infamous White Sea – Baltic Canal was constructed by gulag prisoners at enormous human cost between Lake Onega and the White Sea. Tourism Sinc the 1990s the Volga–Baltic Waterway has grown as a tour boat route to sail and/or motor along or around the Golden Ring of Russia. Heavy power plant transit In 2016, the core of Belarusian nuclear power plant, VVER-1200, which was 330 tonnes, 13 meters high, and 4.5 meters in diameter, was transferred to the plant via the Tsimlyansk Reservoir, the Volga-Don Canal, the Volga–Baltic Waterway, the Volkhov River and a special rail car. Volga–Baltic Canal improvement In Soviet times, the Mariinsk canal system was constantly improved. Two locks were built on the Svir River (in 1936 and 1952); 3 locks were built on the Sheksna River. Major improvement of the Volga–Baltic Waterway took place in 1960–1964, and the new Volga–Baltic Waterway was opened on 5 June 1964. 39 old wooden locks were replaced with 7 new locks, and one parallel lock was built later in 1995. The locks' limiting dimensions are 210 m long, 17.6 m wide and 4.2 m deep, allowing passage of river-sea ships of up to 5000 tons displacement. Such ships were able to sail directly across the big lakes instead of using the bypass canals. Typical travel: Cherepovets to/from Saint Petersburg fell to 2.5–3 days, from 10–15. The modern route sometimes follows the route of the old Mariinsk system and sometimes diverges from it. Six of the canal's eight locks are along 35 km of the northern slope, descending 80 metres. Only 2 locks (which are parallel) are on the southern slope, for a rise of 13 metres, near Sheksna on the Sheksna River, 50 km upstream from Cherepovets. The canal route on the northern slope follows the Vytegra flooded riverbed. Thus the summit pound of the canal between Pakhomovo locks on Vytegra and Sheksna Reservoir dam is 278 km. It comprises an artificial canal (40 km long), much of the Kovzha, Lake Beloye, and part of the Sheksna. The route of the southern slope follows the Shekshna, where it parallels the Rybinsk Reservoir. Current developments The canal is used for oil and lumber export and for tourism. According to the Maritime Board (Morskaya Kollegiya) of the Russian government, 17.6 million tons of cargo were carried over the Volga–Baltic Waterway in 2004, close to its maximum capacity. The Lower Svir Lock