An architect's childhood fantasy treehouse made real.

This Yellowstone geyser may not shoot as high as the nearby Old Faithful, but it erupts for considerably longer.

A beautiful geyser under environmental threat.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

The residents at this Yellowstone wildlife park will certify your cooler as "bear-proof."

Jail from the 19th century that was built by inmates.

When in Idaho, sleep in a giant potato.

No Gordon Lightfoot song, only a barebones monument to greed.

Host to the annual Festival of the Snakes.

This hermitage spanning an Italian river gorge draws pilgrims hoping to heal ailments like arthritis and migraines.

These cinderblock farmhouses were actually World War II radar stations in disguise.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

The world's only museum devoted to the wonders of fluorescence.

The Arctic Archipelago is home to world's largest third order island: an island in a lake on an island in a lake on an island.

An extraordinarily ornate museum in San Diego holds wondrous anthropological treasures.

Smooth basaltic rocks tell a tale of ancient glacial waterfalls.

Massive prehistoric mammals used these stones as oversized scratching posts.

An extensive collection of ancient Egyptian artifacts and mummies.

A mountain range on an active U.S. Navy base hides thousands of mysterious prehistoric rock carvings.

The hidden "ballroom" under a mansion lake was built by a criminal who ate a cyanide pill during his trial.

This precariously perched fortress was once ruled by a crow-worshipping baron.

A B&B on a Victorian lighthouse station in San Francisco Bay.

Fourteen curious and controversial white bunnies sit in a circle near Newport Beach City Hall.