One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

Rising from the sea like a stone monster.

This modern monument to pagan belief looks like it was transported straight from ancient times.

Everyone from Mark Twain to Teddy Roosevelt has a pipe hanging from the walls of this historic chophouse.

This little museum is built on a theater that was once a wildly elaborate speakeasy.

America's post-nuclear-attack chambers of Congress.

Cold War missile launch site which has been converted to a public park.

Concrete crosses scattered across the Arizona scrubland which were used to align spy satellites.

One of the world's largest model railroads is a mind-boggling achievement.

The remains of a 19th century spring, and the site of an infamous unsolved murder.

New York City's smallest piece of private property.

Visit the site of a subway powered by nothing more than air--and lots of it.

A room in New York City that contains 250 cubic yards of dirt worth a million dollars.

One kilometer of thick brass rod laid out before your eyes.

A dark, dank room in subterranean Manhattan was the site of a ghastly murder.

This demolished goliath of American industry once loomed over the depressed town it once made thrive.

Mysterious Spanish catacombs of unknown origins.

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

Tropical paradise strewn with hundreds of World War II wrecks.

The ruins of an ancient island city built atop a coral reef in the South Pacific are spectacular and strange enough to have inspired H.P. Lovecraft.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.