One of the most remarkable caves in all of Iceland was created by a once raging river of lava.

Walk in the footsteps of the gods and straddle two tectonic plates.

The unique waterfall in Iceland's south features a backdrop of geometric black lava columns.

Medicinal spa created with the discharge from a geothermal energy plant.

An encyclopedic collection of mammal penises.

The Icelandic Sea Monster Museum explores the area's history of aquatic cryptid sightings.

Staves, storm-calling, and of course, necropants.

A monument marks the beginning of the longest north-south road in the United States.

The bugs crawling down the front of this office building are almost as big as a '68 VW Beetle.

The design of this historic domed church was influenced by Thomas Jefferson and intended as a statement of religious freedom.

All that remains of Jacques Cousteau's 1960s underwater "village."

An imperial fortress city that incorporated cultural elements from the entire Mughal empire, only to be abandoned the year it was finished.

This historic national park is covered in the stunning ruins of red rock pueblos.

The anatomical-pathological collection of a man who changed surgery.

A metal tree emits eerie, melodic notes on top of Lancashire's Crown Point.

An ancient stone fortress considered by many to be the eighth wonder of the world.

Museum of science fiction, utopias, and extraordinary journeys of the mind.

A French chateau, failed utopian community, odd museum, and Stonehenge replica in rural Washington State.

The famed architect designed this Minnesota gas station of the future with a lookout tower.

A library and museum dedicated to typography.

A fascinating little museum dedicated to the thousands of chemical substances concealed in our food.

Amid the bustle and noise of the Financial District hides a secluded garden oasis above the city streets.

The only natural lake in the world that drains into both the Atlantic and Pacific Oceans.

A Roman-style column in Oregon hides a spiral staircase inside.