The scuba diving training facility was named for the steam that rises from the cave's chimney.

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

All that's left of the quintessential "cabin in the woods."

One part antique store, one part curiosities hodge-podge.

The secret city built by the Manhattan Project.

Ride the subways of yesteryear.

The angel of death appears to weep black tears at this grave marker.

San Francisco's newly reopened hands-on science museum.

Established in the '60s, a family-owned tropical drink bar founded by Ray Buhen, bartender to the stars.

A huge musical sculpture and other art installations on the National Oceanic and Atmospheric Administration grounds.

An acoustic anomaly with a mysterious cause.

This incredible collection of vintage pinball machines can be played at 25 cents a pop.

The private clubhouse for the members of the Academy of Magical Arts.

This geothermal hot spring hides beneath a slowly growing mineral dome.

This knobby, drooping New Orleans oak is a favorite place both for climbing and for meeting giraffes.

One person's lost luggage is another person's treasure.

A hotel and restaurant serving as the mecca of kitsch.

New York City's smallest piece of private property.

A speakeasy takes on Chicago's drinking culture.

A walk-in working camera obscura produces 360-degree live images of the San Francisco coast.

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

This upscale streetwear store is hidden behind a fake Snapple machine in the back of a deli.

A DIY art gallery/music venue/lecture hall dedicated to video game culture.

This abandoned asylum was once a state of the art facility before devolving into one of the most deadly mental institutions in American history.