The world's third-largest crystal sphere has sat in the Penn Museum since 1927 with the exception of one outlandish theft.

A daily replay of the experiment that proved the rotation of the Earth.

The sounds of the world's largest fully functioning pipe organ dazzle shoppers at a Philadelphia Macy's.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

Mural made of 100,000 pieces of hand blown glass, and until recently, the largest glass mural in the US.

Philadelphia boasts one of the best — and most often overlooked — traditional Japanese gardens in North America.

According to legend it was a nap taken under this tree that kicked off the California Gold Rush.

A one-of-a-kind collection of a unique medium.

Panorama exhibition hall in old silent theater with a beautiful backyard garden.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

One of the American Southwest's most extensive collections of Navajo rock art.

The land is full of geologic eye candy, such as otherworldly spires, mushroom-shaped hoodoos, and prehistoric fossils.

A multi-storied adobe complex has been inhabited for more than a thousand years.

One man has carved a number of natural New Mexico caves into psychedelic sandstone temples.

The building stands within a quiet, postcard-perfect New Mexico village.

This popular pilgrimage site offers a hole filled with holy healing dirt.

A small metropolis of Pueblo cave dwellings have been carved right into the hillside of this national monument.

Giant origami sculptures tucked into desert scenery beckon passers-by to explore further.

The winter home of thousands of beautiful snow geese and sandhill cranes.

A futuristic temple of light uses prisms and rainbows to create an atmosphere of peace.

"I did this all while you were watching TV."

If drivers cross the rumble strip on this stretch of Route 66 at just the right speed it plays "America the Beautiful."

San Francisco Bay's ghost town.

The graffiti-covered remnants of a former triangulation station are balanced precariously on this California peak.