Beginning in the late 1940s, the Soviet Union began building deep underground facilities at Russian sites. Those near Chekov and Sharapovo, both outside of Moscow, were notable for their heavily concealed national command authority wartime relocation functions. Disguised to look like research and development facilities to US overhead collection, they thus conveyed a deceptive imagery signature to analysts. Only persistent analysis in the early 1980s by the US Air Force Special Studies Group based on anomaly detection and change comparison over 10 years of imagery coverage eventually exposed the facilities' true purposes.
Designed principally to ensure the survivability of the top leadership and provide continuity in command and control during wartime, these exceptionally well-hidden, deep underground, facilities implied Soviet intentions and capabilities to prepare for protracted nuclear war.