The romantic botanic tunnel feels like a well-kept secret.

Moss and stone turn this waterfall into an otherworldly liquid veil.

An collection of Chinese propaganda posters from 1949 to 1979.

Enormous burial mounds of ancient emperors.

Not one, not two, but three natural bridges remain in this captivating spot post-sinkhole.

A total of 999 stairs lead visitors through a massive hole in a mountain known as the Gateway to Heaven.

For those with no fear of heights: a skywalk 4,700 feet up on a Chinese mountain.

This vertical pinnacle in China was the inspiration for the floating mountains in the movie “Avatar.”

A fifth-century temple improbably built into the side of a cliff.

A part of the world's largest marsh seems to be growing bright red Martian grass.

Crushed coral and crystals give the sand its signature coloration.

The remnants of an archaeological camp stand within Tikal National Park.

Giant kites are flown during this Day of the Dead celebration in Guatemala.

Sparkling, calcite-covered skeletons of children who may have been sacrificed to appease an angry god.

Derelict airplane bodies serve as both home and income for three Thai families.

Twice a day a speeding train passes only inches from the homes of this residential neighborhood.

A startling, centuries-old subterranean marvel hides in plain sight.

Made famous by 'Star Wars,' these troglodyte homes face an uncertain future.

In paradise, feral pigs have claimed an island all to themselves.

They squeal, they nosh, they look like predators.

The abandoned medieval theme park was meant to be the "Disneyland of the Philippines."

An island in the middle of a lake, in the middle of a volcano, in the middle of a bigger lake, in the middle of a bigger island, in an archipelago, in the Pacific Ocean.