Possible Cheyenne mountain D3 (Deep undermountain military base) high security area. The highly sensitive areas in the cheyenne, Dulce and other facilities are protected by these huge doors with scales in front of them. The persons body weight must match their ID clearance for access. If there is a change in body weight of 3 pounds or more the person is x-rayed. This is so no evidence can be smuggled out of these underground facilities internally. There are also CIA, NSA, MI 6 etc stations in front of the doors as in this photo. The lower levels you descend to, the higher security clearance you need. The high security levels of many underground facilities in the world are full of ET's and humans working together. One of my CIA contacts claims that in the underground facility under Nellis air force base there are at least 180,000 grey Zetan bio-robots that are being bred for an army as we speak. There is much  information to suggest that the lowest levels of some bases are just for Zetan grey, Nordic Annunaki and Draconian reptilian collaboration forces and humans are not permitted to enter. According to a NSA contact, the Nordic anunnaki from the Sirius star system are at the top of the chain of command at the Dulce base and have a loose strategic alliance with the Draconian reptilans. The Dracos provide the Annunaki with Zetan bio-robots for abductions and to collect embryos from human females.