After the Second World War, the Soviet Union began developing the Northern Sea Route in order to support the economic exploitation of the vast natural resources of the northern regions. The ambitious plan initiated by the 20th Congress of the Communist Party of the Soviet Union in the 1950s led to the construction of powerful icebreakers to escort cargo ships through the ice-covered waters and extend the navigating season in the Russian Arctic. The flagship of the post-war Soviet icebreaker fleet was the world's first nuclear-powered icebreaker, "Lenin".