A hidden treasure of an abandoned city lies deep in the jungles of Campeche, Mexico.

At least seven hues of blue and turquoise make this freshwater lagoon unique.

The meteor that sealed the fate of the dinosaurs landed at this site, one of the largest impact craters in the world.

It would take you approximately an hour and a half to walk to the end of Mexico's largest pier.

A hacienda that features all things uniquely Yucatán.

One man's fulfilled dream of living on an artificial island made of recycled plastic bottles.

Beach instrument turned bed and breakfast.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

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

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

This Polish cave has housed a dragon, a brothel, and an enduring legend.

Some call this eerie forest of crooked trees the "Bermuda Triangle of Romania."

Once an opulent Art Nouveau hotspot, the Constanța Casino is one of Romania's most beautiful abandoned buildings.

This elaborately decorated, fairytale-like Romanian royal palace is one of the most striking castles in Europe.

This fairy-tale castle would make Dracula (who is said to have been imprisoned there) jealous.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

This massive underground salt mine now holds a sci-fi theme park in its depths.

An old hill fort covered in over 100,000 crosses is a symbol of Lithuanian nationalism and beliefs.

This Nazi ruin was the site where Hitler was almost blown up by a suitcase bomb.

The two abandoned overpasses are among the largest bridges in Poland.

The ghost town left by the worst nuclear disaster of all time is being taken over by nature and urban explorers.

This beautiful natural train tunnel is said to grant the wishes of visiting lovebirds.

A subterranean Holocaust refuge within one of the world's longest cave systems.

Record-holding coffin moonlights as an eatery run by undertakers.