An emerald-green grotto just a short trip from Austin.

This unique structure in suburban Austin is made up entirely of other people's castaways, and constantly changing.

DIY collection of eclectic holdings.

A recreated Stonehenge stands in a country field, complete with Easter Island moai heads standing as sentries.

Scale replica of China's ancient terracotta tomb warriors and Forbidden City are the side project of an eccentric millionaire.

This sacred cavern, 400 feet deep, is home to millions of bats and an ancient burial ground.

A fiery crater has been burning in the Karakum Desert since 1971.

Eclectic architecture in the woods of New York.

Venice's "Island of the Mad."

A small flooded ghost town with a few scattered structures remaining.

The remnants of an early American attempt at missile defense.

Abandoned city hidden from the world by tropical forest and isolation on the coast of Kenya.

A nearly 500-year-old sculpture depicts a man eating a sack of babies, and no one is sure why.

A lake with hundreds of ancient skeletons surrounding it. The surprise is what killed them.