Roswell missile silo's "Located about 25 miles from Roswell, this site is a short distance from a main highway and is visible from the road. This "hardened" area was designed to withstand a direct hit from inbound nuclear missiles."
Abandoned Missile Base VR Tour; "Standing at the entrance, which looks like an emergency access hatch. The real staircase down into the complex was sealed off, and is under the metal lid in the foreground."
Scotland's secret nuclear bunker, "We walk down the 150m entrance tunnel, through the hermetically sealed 3 ton blast proof doors into an environment which reveals to us one of the darkest periods of Scotland’s history and the worlds."