A Manhattan courthouse hides a small but scathing memorial to Holocaust injustice.

Manhattan's lighthouse, erected at the insistence of the unsinkable Molly Brown.

The hidden jewel of Disneyland: a members only playground for the Disney elite.

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

The only diamond mine in the world where you can keep what you find.

A collection of full-size movie monsters opened to the public.

A pair of slides and a tree-lined stair corridor have been an urban oasis for nearly 40 years.

Julia Morgan's Moorish-Gothic labyrinth of fountains, trees, natural light and Oakland's notable dead.

A secretive collection featuring objects that were designed specifically for U.S. intelligence operations.

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

These eerie outliers of the lightning bug family glow a mysterious blue color.

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

The final resting place of a space program monolith.

Tiki luxury on Nob Hill.

Visible below the waves are memorials to the city's Gold Rush dead.

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

This upscale streetwear store is hidden behind a fake Snapple machine in the back of a deli.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

This woodland architectural installation acts as a camera obscura for the heavens.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

A reproduction of earth's many biomes.

New York City's smallest piece of private property.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.