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

A park where people have been going to feed friendly pigeons since the 18th century

An exhibition devoted to the life (and posthumous taxidermy form) of the last known representative of the Pinta Island Tortoises.

The "lovely red Vega" of the legendary record-settling pilot.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

Home to items never before seen by the public.

Perhaps the most scandalous statue of America's first president.

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 John Snow Memorial marks the epicenter of London's 1854 cholera epidemic.

Island where motor vehicles are banned -- home to the only carless highway in the United States.

This striking art museum holds an amazing series of curiosity cabinets.

A place to eat for on-the-run agents and espionage enthusiasts.

A statue honoring 44 continuous years of greeting passing ships.

The beautiful behemoth is one of the largest trees of its kind in the United States.

Acres of natural wonders left behind by a socialite-turned-gardener.

A popular winter vacation destination for migrating monarch butterflies.

The key to turning shifting dunes into the green oasis of Golden Gate Park.

Once close to extinction, there is no shortage of elephant seals on the beaches of Año Nuevo State Park.

The space-age building is home to one of the few remaining rotating restaurants in America, and the only one that inspired a 1980s sitcom.

A burnt orange monolithic dome structure perched on a hillside near Interstate 280.

Home to the "Circus" trees created by Axel Erlandson.

The giant pair of sexy legs sticking out the window of this costume store have become its main draw.

This private residence was the template for one of the most beloved television homes of all time.