Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

One of the most scenic stretches of road in America winds between some of the country's oldest trees.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

The "world's biggest dinosaur" once housed a creationist museum in its abdomen.

This grand gothic brewery has been pumping out suds for over a hundred years.

A legendary speakeasy bookstore returns from the brink.

A hidden network of subterranean passageways lies tangled beneath Indianapolis' bustling City Market.

A self-built castle made by a mysterious man.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

Hidden in an ordinary Midtown building is a one-room museum dedicated to the greatest escape artist.

An abandoned stretch of highway, deteriorating next to the operational one.

An acoustic anomaly with a mysterious cause.

Breathtakingly blue walls shimmer inside the "Glacier Behind the Town."

A modernist landscape of water and sci-fi concrete.

Seemingly grown on some other world, these New Mexico rock formations look like a disused science fiction set.

The abandoned husk of a mental institution that failed to save a Jazz Age icon still sits nearly unchanged.

The one-stop shop for all of your superhero (or evil arch-nemesis) needs.

This New Orleans tree is filled with hidden chimes that produce a carefully tuned melody.

Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

A breathtaking array of ancient Pueblo structures and artifacts counterintuitively preserved by neglect.

The world’s oldest and biggest bookstore stocking only mystery, crime fiction, espionage, and thrillers.

A castle that was built stone by stone by an eccentric journalist.

An underwater city for the dead.

In the middle of an extremely unforgiving and desolate high desert is the most secret military facility in the world.