Once home to over 8,000 exiled Hawaiians suffering from Hansen's Disease.

The largest known meteorite on Earth was too big to move.

A monument to the art of slicing people open.

Thousands of well-dressed mummies below a monastery.

This huge pile of volcanic boulders hides a stunning network of secret grottoes.

World's first "penitentiary," meant to be humane, drove men insane.

Statue of a decomposing prince that once held his heart in its hand.

Two stunning 17th-century libraries and a cabinet of curiosities.

This frozen tunnel in central Alaska is both an engineering feat and a valuable climate classroom.

Remote, volcanic island that Darwin, Hooker, and the Royal Navy shaped into a thriving, artificial ecosystem.

The world's largest statue of Mao Zedong looks out over the city where he discovered Communism.

China's very own Atlantis is an ornate dynastic city resting at the bottom of a lake.

A marvel of Byzantine engineering under the streets of Istanbul.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

Gleaming self-built castle towers made from beer cans and inspired by "Vitamin Mary Jane."

A sacred lake composed of over 300 separate pools of highly concentrated minerals.

An abandoned NSA listening post on Berlin's "Devil's Mountain."

More than 200 statues filled with cryptic symbols give this park spot an aura of horror vacui fantasy.

Thousands of exquisitely carved stone water storage wells, hundreds of stone steps fill this exquisite medieval stepwell.

Malaysian fireflies create a dazzling display as thousands light up in unison.

This former insane asylum now holds a pathological anatomy museum.

A geological bull's-eye visible from outer space.

An underground mansion with fruit-bearing trees and grapes growing beneath the surface of central California.

This golden temple is surrounded by hundreds of stone tablets that comprise the "world's largest book."