This Pennsylvania cave holds evidence of the oldest known inhabitants of North America.

House of vintage taxidermy and Steampunk sculptures in a quiet Pittsburgh neighborhood.

These disused steel furnaces are now haunting ruins that may one day be a national park.

Mutant vegetables, transgenic mosquitos, and atomic rodents span the walls of this one-of-a-kind museum.

This public park was the site of the largest civilian disaster of the Civil War.

Despite being stolen multiple times, this civic electrician's street corner Snoopy won't be stopped.

Found art has transformed this Pittsburgh neighborhood into a psychedelic dream.

One of the steepest streets in the United States makes an intriguing challenge for cyclists.

This church in Pittsburgh is home to the largest collection of religious relics in North America.

The taxidermied remains of the "last wild grizzly bear in California" and of the symbol of the state of California.

San Francisco's first World's Fair, dedicated to the wonders of California.

The stones that traveled from Spain to eventually become a holy place for San Francisco's nature worshippers.

Over 315,000 preserved amphibians and reptiles in jars.

A classic advertising icon immortalized in regal bronze.

Alleyway plaque commemorating the death of a fictional character in The Maltese Falcon, not far from the author's home.

Since 1973, this block has been home to the most concentrated collection of murals in San Francisco.

This giant head is all that remains of a once proud statue that survived an earthquake but not a fall off of a wagon.

Deco Modern sculptures of the people of the Pacific, cast for the 1939 Golden Gate International Exposition.

A favorite haunt of dinosaur loving children and hallucinogen loving hippies alike.

Its buzzing collection honors vibrator history.

Half of a house.

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

The only theatre in the world constructed specifically for sound movement.

The tea room that pushed the boundaries of adorable straight into...we can't find the words.