The largest prehistoric ruins south of the Sahara, once a powerful center of international trade.

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

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

Guitar made of trees, dedicated to a man's lost love.

We heard you like volcanoes so we put a volcano in your volcano so you can die for sure...

Steaming blood-red hot spring from hell.

Malaysia's first and only glass temple.

This famous archeological mystery may be an ancient example of movable type.

Three buildings constructed of over 25,000 multicolored glass bottles.

The remains of an encyclopedic sculpture garden later used as an internment camp.

Collection of nearly 500 concrete figures sculpted by the late Veijo Rönkkönen.

Social outcasts and cannibalism in Stalin's Soviet Union.

Countless stories attempt to explain Poland's mysterious J-shaped trees.

Twelve sculptures designed to make their best showing with the coming or going of the sun.

Unique geological formations in China, featuring some suggestive shapes.

Relive a Polish uprising via an enormous, century-old cyclorama.

Figures of unknown origin carved into the surfaces of underground caves.

Semi-mystical manmade towers of rocks decorate this rocky seaside.

Nazca pilgrimage site covering 370 acres is a popular stop for archeologists and looters.

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

This tiny Bulgarian town offers a stunning location in the mountains and a storied history.

An arresting arch punched straight through a mountain provides one of the most scenic spots, and challenging climbs, on the planet.

The once-dying town of Sheffield, Tasmania has reinvented itself as a village of painted wonders.

Abandoned castle was once a grand example of Russian privilege, built exclusively to win a frivolous bet between noblemen.