In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

An artsy hidden staircase leads to breathtaking views of San Francisco.

A psychedelic labyrinth on the San Francisco bay.

This quirky UFO-shaped curiosity is often mistaken for the airport’s control tower.

Historic funicular railway, believed to be the shortest railroad in the world.

Scores of vintage street lamps shine along L.A.’s Miracle Mile.

These delicate buggers are some of the rarest fossils that have bubbled up from the Tar Pits.

High on a hill overlooking Los Angeles lives a world famous, high-power conical Tesla Coil.

The legendary building that needed ghostly approval before being built.

This iconic L.A. bookshop is housed in an abandoned bank—both symbolic and chic.

A dramatic coastline that’s home to a rare pine tree.

A hidden courtyard houses early 20th-century plaster masterpieces.

Built for an exposition in 1915, these horticultural displays have stood the test of time.

North America's largest accredited model railroad museum.

Behind this beachfront shop lies a spectacular, colorful sea cave with an equally colorful past.

A hidden oasis just north of Chicago's Chinatown.

A relic of the Cold War in Chicago.

Huge abstract sculptures of the Puerto Rican Flag.

A spectacular remnant of an Adler and Sullivan masterpiece that was destroyed in 1972.

A 400-foot-tall tall map of Chicago makes this once-ignored building stand out.

One of the few remaining relics of the meatpacking hub that made Chicago the "hog butcher to the world."

To find the "unicorns of the deep" you've got to go downstairs.

These mansions date back to Chicago's days as a brewer's paradise.

The unluckiest U-boat in the entire German fleet is now on display in a Chicago museum.