The Moscow Metro (Russia)
This subway system is also a large subterranean system of secret trains and bunkers. It is a hidden city beneath Moscow. Most of them were built by Stalin during the Cold war. There are only few first hand notifications of a secret metro’s existence. According to report of the United States Department of Defense in 1991, the facilities of this bunker are interconnected by a network of deep interconnected subway lines that provide a quick and secure means of evacuation for the leadership. The leadership can move from their peacetime offices through concealed entryways in protective quarters beneath the city. They are estimated to be 200-300 meters deep, and can accommodate an estimated 10,000 people. A special subway line runs from some points in Moscow and possibly to the VIP terminal at Vnukovo Airfield.