This whimsical stacked cabin looks like something out of a children's book.

Breathtakingly blue walls shimmer inside the "Glacier Behind the Town."

The world’s tallest outdoor lift stretches along the stone pillars that inspired the floating mountains in the movie “Avatar.”

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

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

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

This concrete amphitheater offers an unforgettable view of one of Mexico's most beautiful canyons.

A pre-Hispanic pyramid in the middle of a tourist district in the Canary Islands.

Marvel at this massive waterspout fueled by the incoming tide.

Volcanic rocks ground down into sand make this Spanish beach as black as night.

The best place for scenic views of the DMZ and North Korea.

Secret North Korean passage discovered below the world's most dangerous border.

A hotel masquerading as a medieval castle overlooks a Mexican city.

Peaceful gardens hide an underground torture museum.

The world's second-tallest flagpole stands proud despite dropping rank.

This ancient Silk Road outpost overlooking the Wakhan Valley is miraculously still standing.

This medieval citadel once guarded the western entrance of the Pamir Highway.

The largest dam in the world and the site of a potential disaster.

The world's largest wooden structure.

Village situated on a narrow volcanic escarpment.

An isolated village literally built into the crevices and rock formations of a mountain.

A Spanish town built into the cliffs.

This Navarrese cave's history of witchcraft and pagan ritual is not just embraced, but recreated each year.

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'