In December 1937, the boat was founded in Leningrad in 1939 August 16 launched. In the Northern fleet enlisted September 17, 1941. In the first combat campaign mounted boom in the Strait best-sung, consisting of 11 min, and the morning of 11 November 1941 in the place was blown up and sank the Norwegian transport called "Bessheim".

This ship has a glorious military history. Near the island Inga in July, more 5, 1942 "K-21" found a squadron of German ships and attacked the enemy. The result chetyrehetapnogo volley of enemy battleship "Tirpitz" was seriously damaged and was forced to return to base in Norway.

For all time of war "-21" was sunk 17 German transports and warships, made twelve military campaigns and implemented six mine productions.

In Severomorsk, probably not to meet someone who would not know the main attraction, which symbolizes the history and purpose of the city of sailors. Almost three decades on eternal guard is a legendary boat - red banner To-21, which is a branch of the Museum of the Northern fleet. The submarine is located on the square of Courage. 70 years ago the boat was solemnly raised a naval flag, and since then, the submarine is on the watch in the Arctic.

In our days in the compartments of the submarine are presented, which describe the actions of WWII and the formation of submarine forces in the North in the postwar period. Personal items, photographs, awards submariners and the documents of that time better than any historian will tell about the heroism of people in his time leading the boat in the fight.

However, the main is the submarine. In the four compartments of the saved combat situation – here it is possible to literally touch history: batten down the rack, look into the periscope – feel like a true submariner.

During the war years "-21" under the command of Nikolai Lunin, Arcady Zhukov and Samara Aranova made 12 military campaigns. The crew of the submarine scored 17 victories.
For exemplary accomplished mission, for heroism and courage of the crew of the "K-21" in 1942 was awarded the order of red banner. In General, during wartime submariners submarines 102 were awarded military orders and 35 medals.

In the fifties of last century, the ship served as a training simulator for sailors, practicing fighting skills for survivability. In this capacity, he existed before the moment when the military Council of the Northern fleet signed a resolution is to turn the submarine into a memorial complex immortalizing the memory of the valor and military exploits of submariners in the difficult war years. "K-21", affectionately nicknamed by sailors Katusha, has found a permanent Parking place next to the berths of the other warships in 1983, the year marking the fiftieth anniversary of the Northern fleet.

To celebrate the 70th anniversary of the submarine to pay tribute to the heroism of the sailors came representatives of the Murmansk regional administration, the students of cadet classes, the military. The meeting took place. Solemn March were sailors and cadets on the area of Courage, symbolizing the continuity of generations. To the body of the legendary boat wreaths and flowers were laid. Was celebrated, and the submarine remained at historic watch.

In the period 2008 – 2009 was renovated Museum, has also been updated exposition. The exhibition of the Museum is constantly updated, providing visitors with an opportunity, having been in the case, to get acquainted with the traditions of the ship and the Northern fleet. In our days the submarine performs equally important mission of military-Patriotic education of the younger generation.