From the severity of the arms race in the Cold War, Russia became the second largest naval power in the world. To oppose the aircraft carriers of the powerful US Navy, the Russian Navy created a new type of guided missile nuclear submarines known as the Oscar class. Massive Oscar I-class submarines were first used in 1982. Later, the Oscar I class submarine developed into an even larger Oscar II class with an impressive displacement tonnage of 18,300 tons and a total length of 154 metres. Despite their gigantic size, Oscar II class submarines were capable of high maneuverability and damped movement. In January 1995, the 10th Oscar II series submarine, the K.141 Kursk, commissioned with the Russian Northern Fleet and commissioned to defend the northern borders of the country. Like other Oscar II class nuclear submarines, the Kursk had a two-layer construction consisting of an 8.5 diameter pressure-resistant inner hull and an outer hull. At the distance of approximately 3.5 metres between these two fuselage layers, there were twelve SS-N-19 rocket launch tubes with a range of 550 km on each side. To accommodate these rocket launchers, the 154m Kursk was built extra wide, and this giant of a nuclear submarine became known for its total circumference of 18.2 meters. The Kursk sank five years later on August 12, 2000. This incident would mark the most tragic episode in the entire Russian submarine history. At 11:30 a.m., 140 km before the seaport of Severomorsk (Northern Fleet headquarters), an explosion of unknown cause sent the Kursk 100m underwater to the bottom of the Barents Sea. Despite the efforts of the Russian Navy, as well as British and Norwegian rescue forces, the 118 men on board, including the captain, could not be rescued.