An Ethiopian "Jerusalem" featuring a church hewn out of a single rock.

A Turkish ghost town abandoned in a population exchange with Greece.

Beijing's World Park offers the excitement of international sites without the travel.

Reverend Jen's unique museum/living room showcases her troll collection.

Green labyrinth formed by a karstic maze hidden in a preserved oak forest.

The world's largest solar furnace uses 10,000 mirrors to concentrate the sun's rays to generate power.

A Surreal flight of architectural fancy in Vietnam's Central Highlands.

A massive underwater sinkhole made famous by Jacques Cousteau.

This fantastical icy castle is built anew every winter.

One of the world's most complex timepieces.

Twenty-seven massive radio antennas on the high plains of New Mexico search for life on other planets.

The world's largest Tibetan refugee settlement.

This small chapel is built of human bones and decorated with a golden skeleton.

Amöneburg is a town perched on top of a basalt mountain in the middle of an ancient meteor crater.

A beautiful, dense forest in the shadow of Mount Fuji, with a tragic reputation.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

Mountain of unimaginable riches that bankrolled the Spanish Empire, complete with its own underworld god.

Last remaining nuclear missile base in Ukraine.

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

19th century pendulum and a clock restored by a rogue group of guerilla artists.

Subterranean place of worship in Indonesia.

Highly unusual subterranean stupa and adjacent cave monastery.

A beautiful oasis town dating back to the Roman period still serves as reprieve from the brutal summer sun in Libya.

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