This crumbling UFO is one of only a few remaining "moveable ski chalets" of its kind.

The walls of America's oldest masonry fort famously "swallowed" cannonballs.

Launched by Napoleon's soldiers more than 200 years ago, a cannonball remains embedded in the tower wall.

Every equinox this Maya pyramid puts on a spooky ancient light show.

Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

A magical sinkhole on the Yucatán Peninsula is adorned with mini waterfalls and hanging vines.

This stretch of highway is said to be haunted by ghosts of settlers whose graves were paved over.

A tiny village church in dramatic surroundings.

A second generation sun-powered marvel lights up the night.

This seemingly out-of-place gas station by the Watergate hotel was once described as the most expensive gas station in the world.

One of the oldest living oak trees in the Southeast.

The world's longest known cave system.

A jaw-dropping brutalist space church seems to have crash-landed in the middle of America.

Behind this beachfront shop lies a spectacular, colorful sea cave with an equally colorful past.

A relatively obscure antihero from the Marvel Comics universe adorns a wall inside Iceland's main airport.

This little museum has an exhibit devoted to the elusive forest denizens.

Macabre astrological automaton clock dating to the late 1400s.

Go inside to really appreciate this 500-year-old technological masterpiece.

A bit of retro transportation flair preserved in the world's largest department store.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

Hidden behind Lincoln's head is a chamber containing enamel plates documenting American history, sealed in a teakwood box in a titanium vault.

Some of the world’s most popular songs came out of this building.

Icelandic folklore says this giant boulder was ripped from the mountains and placed at its current location, where it became home to elves.

In Florida, these naughty monkeys live on their own mini-monkey Alcatraz.