From the 1958 until 1992, the Greenbriar Resort in White Sulfur Springs, West Virginia sat on top of a secret. Underneath was a huge fallout shelter designed to accommodate members of the US Congress and their aides in case of a nuclear attack.
The 18 dormitories could sleep 60 people each on metal bunk beds. Each had a shower, toilets, and small lounge.
The clinic covered 600 square feet and had 12 beds, an operating
and intensive care room. It would be manned by military doctors and nurses.
During its life, it was constantly maintained in a state of readiness. Communications, electronics, and mechanical equipment was updated as needed. Supplies were cycled to insure freshness.
A complete TV and radio studio was equipped with modern facilities including a 75' telescoping antenna hidden on the top of the rise beside the new West Virginia Wing. Congressmen and Senators would broadcast to survivors important information, most importantly that the central government was still in operation.
The project was abandoned after a 1993 Washington Post article brought it to the public's attention. Link -via Atlas Obscura