ABC News' David Muir reports from West Palm Beach, Fla.:

We all recognize the iconic images of " Camelot," the White House John F. Kennedy lived in with his wife and children starting in 1961.

The photos of kids playing in the Oval Office, the family vacationing on the presidential yacht, the Honey Fitz.

Related: Complete ABCNews.com coverage of 50 years of the Kennedys

But behind those golden images was a much more black-and-white reality. The country lived with very real fears of the Cold War, during a tense nuclear standoff with the USSR.

Christine Romo/ABC News

Away from the public eye, secret bunkers were being built for the president and his family, in case of a Cold War disaster.

Today, we took a 10-minute boat ride, the route President Kennedy himself took, from the so-called "Winter White House" in Palm Beach, Fla., to a man-made island that houses one such bunker.

Fifty years ago, the shelter was camouflaged by trees, accessed through secret entrances and deep tunnels.

More related: 50 years later, why we're still obsessed with the Kennedys

The "Kennedy Bunker" was built in 1961 by the Navy in less than two weeks, protected by 12 feet of concrete and steel.

The fallout shelter sat fully stocked with 15 sets of metal bunk beds, a transmitter a.m. radio, survival kits (including water stored in lead cans), rations, radiation detection kits and a decontamination shower - showing just how real the fears of a nuclear war were.

The bunker was, fortunately, never used, and the White House didn't even acknowledge its existence until 10 years after President Kennedy's assassination.

Christine Romo/ABC News