A wall of chewing gum moonlights as collective art.

This former coal gasification plant found a curious second life as a popular public park.

A huge musical sculpture and other art installations on the National Oceanic and Atmospheric Administration grounds.

A giant Troll lurks under one of Seattle's oldest bridges.

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.

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

These azure waters were thought to lead to the Mayan Underworld.

If you can look past the nearby sewer pipes, this urban sinkhole grotto is a mini-paradise.

An ancient system of freshwater caves filled with animal bones, including that of species long-extinct.

Underwater art project will double as a massive artificial coral reef to help regenerate the damaged ecosystem.

The ancient latrines of the Greeks, in all their public glory.

Seven early Christians were sealed into a cave where legend has it they slept unharmed for centuries.

Carvings in Turkey's Marble Road may have directed ancient Romans to a hidden brothel.

The alleged house of the Virgin Mary is tucked away in a park and nature preserve on Mt. Koressos in Turkey and is holy to both Catholics and Muslims alike.

A sharply wedged sundial marks the point at which each day in the United States begins.

This open air archeological site houses almost as much wildlife as it does classical religious artifacts.

The Greek island's old British cemetery feels like a forgotten garden.

The ghost town where the villagers refuse to leave.

Local lore says two enemy dragons live within these breathtaking mountain lakes.

This little-known, 35,000-specimen collection in Greece is a lepidopterist's dream.

A grotesque collection of wax limbs depicting the symptoms of venereal disease.

This gem is often wrongly overshadowed by the larger, newer Metropolis church in Athens.