Deep in the Negev Desert, the world's tallest solar tower looks like a sight straight out of science fiction.

This lost city belongs to one of the earliest civilizations in the world.

Shakespeare, David Bowie, Dr. Who, the Saxons, Druids and Romans are all claimed to have all made their mark on these massive man made tunnels.

Mount Tambora is the site of the largest and deadliest volcanic eruption in recorded human history.

An abused and forgotten metropolis, abandoned for centuries.

Miles of man-made caves and tunnels are currently used for cultivating mushrooms.

Founded by members of the Tohono O’odham Nation, this one-room joint's James Beard–winning fry bread is light as a cloud.

Ruins of the Crusaders' headquarters.

This picturesque castle in Poland has a rich history, including a legend that ties it to lost Incan treasures.

Twelve hundred stone carvings guard this off-the-beaten-path Buddhist temple.

One of the largest ancient geoglyphs in the world is a tall desert god used for predicting the weather.

Enormous underground chamber built to detect 'ghost particles' of the universe.

England's most famous front door has an accidental doppelganger.

The remnants of an early American attempt at missile defense.

Hauntingly beautiful totem poles left by the Haida.

This hilltop warren of monastic dwellings is the result of centuries worth of Mongol attacks.

Winter weather reveals a large Italian marble crucifix drowned beneath Lake Michigan.

Europe's official "zero-level," the equator of elevation.

A humid oasis combines recreation with exploration in a unique underwater cavern.

This experimental utopian "city of the future" in rural India may hold a dark secret.

Millions of glowing microscopic organisms light up the waters of this luminous lagoon.

The ghostly remains of what was once the world's richest copper mine.

A war-torn Olympic relic is being overtaken by graffiti and nature.

You can row a boat through this ancient underground reservoir.