One of the world's largest pyramids stands within El Mirador, the "lost city of the Maya."

Volcanically heated hot springs.

Hidden deep in the Guatemalan jungle is a turquoise paradise of natural pools, caves, and waterfalls.

This Irish show cave is said to have been the site of a Viking massacre that claimed 1,000 lives.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

Local legend says there's treasure hidden within its crowded graveyard.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

A complex and beautiful system of rice terraces covers a million acres over the mountains.

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

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

A sacred mountaintop temple offers a fine cup of tea to visitors who can survive the journey.

The world's longest outdoor escalator takes visitors to the top of China's largest dam and is also shaped like a dragon.

A canvas of crops grow from vibrant red soil in this terraced farmland.

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

The most famous location in China was home to whole dynasties worth of imperial rulers.

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

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

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

A nearly unconquerable island-fort in the Indian Ocean.

A centuries-old lookout post still sits atop a natural stone spire.

A centuries-old fortress city lies in ruin.