The only surviving sidewalk clock in Brooklyn.

This historic tower in the California desert promises visitors a "vortex of good vibes".

A hidden "place of interment for gentlemen."

Macabre headstones carved with winged skulls, dancing skeletons, and pithy reminders of impending death.

The world's largest kaleidoscope, designed by a 1960s psychedelic artist.

Two rocks in a perpetual kiss and one of "the most romantic spot in America."

North America's largest accredited model railroad museum.

Museum dedicated to the preservation of surf culture.

The Giant Lemon of Lemon Grove.

A collection of more than 12,000 shoes, displayed in a building shaped like a shoebox.

America's most famous piece of self-built architecture.

The ghostly remains of an accidental sea.

An historic and oft-filmed spot for musclebound iron pumpers on the Pacific coast.

A crumbling hospital from the 1850s on Roosevelt Island.

Infamous marsh filled with toxic waste, World War II-era London rubble, and dead mobsters galore.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

The first American department store, and home to the largest operating musical instrument in the world.

Collapsing castle on the Hudson river was once the storage site of military surplus business.

The "world's biggest dinosaur" once housed a creationist museum in its abdomen.

A gigantic 10-foot tall stone man.

In its day this historic fort held 100 cannons pointed in almost every direction to protect New York.

An uber-secure, windowless tower of doom in the center of Manhattan is an NSA spyscraper.

One of the final grand railway depot hotel complexes is slowly being restored to its former glory.

This outdoor gallery of graffiti-covered walls pays homage to the past, present, and possible future of street art.