This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

Once the future of underwater combat, this old sub is now open for visitors to muck around in.

This museum sits on the site of a decommissioned military communications base.

This shop for all your super spy needs hides an educational secret.

A giant gun barrel in Barbados that once hoped to shoot outer space with science.

A terrific purveyor of natural history objects and curios.

An impressive array of unique homemade planetariums.

Its diverse collection of computers and technology spans the ages.

A Cold War site complete with rusty structures, hiking trails, and beautiful views.

A metal ring in the middle of the road marks the exact spot where the Soviet satellite crash-landed in 1962.

Monty Python fans will recognize this abandoned mine as the Cave of the Killer Rabbit of Caerbannog.

A steampunk airship "floats" above Hamilton Gardens delivering plants and compost.

Housed in a century-old building, this museum's dedicated not just to soft drinks, but to the free enterprise system.

Wayne Newton's sprawling estate is now open for visitors to catch a glimpse of his "heart and soul."

Nevada's largest cactus collection stands outside a candy mogul's small factory.

Exact replica of the ancient monument, but much, much lighter.

This institution celebrates the happy accidents of uncommon sticktoitiveness.

With its peeling paint and faded sign, this theater-turned-recycling plant is a nostalgic relic of 1950s Americana.

A tiny museum in Esperance, Australia, displays a bunch of space debris from NASA’s Skylab.

Cat art as far as the eye can see.

A museum in south England celebrates the amphibious vehicles that cruise on a cushion of air.

Ever wanted to can Spam?

The oldest family-run luncheonette in New York, last renovated in 1948, still serves food and drinks the old-fashioned way.

Installed at a chaotic intersection, this gave London traffic cops a place to hang their heavy woolen coats.