Soon after the Russian invasion of Ukraine in 2022, satellite images taken over the forests northeast of Moscow began revealing something that sent chills down analysts’ spines.The mysterious Cold War facility known as Sergiev Posad-6 was suddenly witnessing a rush of activity. Subsequent satellite images confirmed that ten enormous new buildings were rising up out of the wilderness, a massive expansion of the site.Off-limits to international inspectors, the complex system of underground tunnels, reinforced chambers, and specialized laboratories was designed to hide horrifying secrets and invisible weapons, threats that respect no borders and are impossible to recall once let loose.As the conflict in Ukraine rages on, could Russia be gearing up to unleash humanity’s worst nightmare?