The President John F. Kennedy Bunker

Just under the surface of Florida's Peanut Island, located just off the coast of Palm Beach, is a nuclear bunker that was created specifically to house President John F. Kennedy and his staff in the event of a nuclear attack while he was on vacation in the area. 

Created in a scant ten days by the armed forces' most adorably named division, the SeaBees, the cavernous safe house was located a harried ten minutes away from JFK's Palm Beach resort house where the young president spent a great deal of time with his family. With the outbreak of the Cuban Missile Crisis a top priority became making sure the commander-in-chief was never far from a bunker, and so the Naval engineers created a facility that could house the POTUS and up to 30 others for around a month. The corrugated body of the shelter was then buried under 25 feet of soil, lead and, concrete.

Luckily the bombs never came. After his JFK's death, the bunker was all but forgotten and fell into disrepair, taking on water and natural detritus. It wasn't until the mid-90's that the site was leased by a museum group and work began on restoring the site to its original state. The bunker museum opened in 1999 allowing visitors to tour the disused shelter which has been restored to the condition it would have welcomed the president in. There are even replica rations.   

Update October 2017: The bunker is closed and all the artifacts were transferred to the Palm Beach Maritime Museum.

Update November 2018: The site itself is currently closed because ownership went back to the county. The new date for it to be opened is not known at this time.  

Update July 2021: The site is still closed.