The only quarter of the Old City not dedicated to a major world religion.

Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

The oldest surviving botanic garden in the United States.

Where America's first doomsday cult awaited the end of the world.

Berkeley Hot Springs presents to you "the only outdoor monument to presidential bathing."

This town is home to the world’s largest arch constructed entirely of elk antlers.

This giant disembodied horse head seems to balance impossibly on its nose.

An abandoned network of military bunkers and tunnels open for anyone willing to descend into the darkness.

Native American burial mounds? Giant gopher dens? No one knows what created the Mima Mounds.

These memorials built by an eccentric bachelor on the side of Interstate 5 cause both wonder and traffic accidents.

Only known mainland rookery of the threatened Stellar sea lion.

A massive sea stack famous for its appearance in The Goonies.

100-year-old shipwreck you can walk up to at low tide.

The magic's in the hole!

The U.S. Navy's last diesel-electric submarine rests half-submerged in the middle of Portland.

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

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

These elusive, isolated rodents evolved into a distinct, locally iconic subspecies.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

See massive fossils that are over 200 million years old in northeastern Arizona.

The national park was once a plantation estate.

This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

The final resting place of an unidentified revolutionary soldier sits behind a Virginia church.