The biggest pinball arcade in the world has over 600 pinball machines, and 300 arcade machines.

This crumbling UFO is one of only a few remaining "moveable ski chalets" of its kind.

These tourist trap caverns are said to be the former home of a legendary Pennsylvania Hermit.

An earthwork sculpture built by Robert Smithson in the Great Salt Lake only reemerges during drought.

These Great Lakes sea caves accessible by boat in the summer turn into temples of ice reachable by foot in the winter.

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

San Francisco Bay's ghost town.

In the remote high desert of New Mexico, a strange array of poles beckon fury from above.

These Pre-Columbian petroglyphs contain representations of birds, deer, hunters, and even some early Native flute players.

This historic national park is covered in the stunning ruins of red rock pueblos.

Moonbows over Kentucky.

A 24-hour vending machine restocked daily with homemade full-sized pecan pies.

Friction between grains of sand cause a curious "singing" sound.

An obscure waterfall that looks like something out of a fantasy novel.

The remnants of two World's Fairs are here, complete with a 12-story globe, a mini-Manhattan, and a UFO-shaped pavilion.

California's own medieval Italian castle, authentic down to the 300-year-old iron maiden in the dungeon.

San Francisco's urban bison herd has persisted in the face of extinction, development, and disease.

Bad farming practices caused this unnatural natural wonder.

One of the largest, oldest, darkest, quietest motel rooms in the world.

America's only nuclear missile silo open to the public.

The Grand Canyon of Texas.

The "Fun Spot of the Desert" is now a haunting ruin, and a reminder that putting a water park in a desert is a bad idea.

One of the most scenic falls in Massachusetts has a history of death and grim legend.

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