This short pedestrian span is also known as the "Fairy Walking Bridge" because it looks almost magical.

Mirrored floors and arched shelves create the illusion of an infinite tunnel of books.

Massive series of 45 caves and over 51,000 sculptures carved from cliffsides in China.

Rock-cut caves and 7,000 Buddhist sculptures carved into the nearly sheer face of a sandstone mountain.

A tunnel dug through the side of a mountain by hand provides convenient yet death-defying access to a small village in China.

Snow-capped peaks, colorful waterfalls and stunning vistas on the edge of the Himalayas.

The latest in a series of long glass bridges suspended at terrifying heights.

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

This abandoned fishing settlement may well be the greenest village in the world.

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

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.

Intensely colorful calcite pools in Southern China.

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

Housing the groundbreaking maps and globes of Gerard Mercator.

Lavish royal estate punctuated with heated greenhouses.

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

This tri-part waterfall is a little bit of fairytale beauty in the heart of Luxembourg's Little Switzerland.

This noble mash-up in eastern Luxembourg is part Medieval, part Renaissance, all castle.

Once the local rulers had gone these enchanting ruins housed common folk in an almost real life fairy tale.

The steepest classic funicular in the world glides along a dizzying incline.

A breathtaking bridge that crosses a vast gorge over a river's torrents, and has a tale of a devil architect attached.

This is not only one of the oldest collections in Europe, but also possibly the most beautiful.

This 170-year-old Swiss guesthouse built into the side of a mountain is best accessed by a cable car.