This subway system is called "Metro 2" and is located under the civil subway in the very centre of Moscow. Right now we're going to go down for 110 meters in the area of Red Square.
The secret special subway system can be built in many ways and for different purposes starting from evacuation of the Russian generalship and finishing with the systems of special communication of various bunkers belonging to all possible agencies and structures (already finished ones and those being still built).
It's an amazing place with red light and numerous signaling sensors, guard posts 24/7 and constant patrol of duty staff.
These tunnels are stretching for many kilometres under Moscow and one can walk along them for hours... These cables seem to be endless, they connect numerous basements of interesting buildings belonging to various institutions.