A tiny theater hidden in an alley plays a constant stream of short silent films for anyone willing to peer through the peephole.

A three-story copper skybridge connects two Manhattan buildings with Art Deco luxury.

A celebration of capitalism in Midtown.

A reproduction of earth's many biomes.

Historic marionette theater features thousands of handmade puppets and free cups of ice cream.

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

A huge musical sculpture and other art installations on the National Oceanic and Atmospheric Administration grounds.

A sprawling Baroque park with 300-year-old hydro-pneumatic waterworks.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

This medieval castle overlooking the Elzbach river looks just like it did hundreds of years ago.

An acoustic anomaly with a mysterious cause.

A self-built castle made by a mysterious man.

Oh, just a motel on the edge of the desert decorated with thousands of clowns conveniently located next to an abandoned graveyard.

A Swedenborgian glass church surrounded by redwoods sits perched atop a massive landslide area.

World-famous, Pink's still manages to keep its prized cult fetish status.

Wedged between two buildings at the Great Ormond Street Hospital is this secret music installation.

Welcome to old Florida, where a 1940s mermaid show is still enchanting visitors.

This unmarked and unloved Manhattan subway grate created one of the most iconic images in American cinema.

Finale of "William Tell Overture" can be heard as drivers pass over grooves in the road.

Stalactites and stalagmites in a beautifully lit cave.

The original "capsule building" is a masterpiece of Metabolist architecture.

A modernist landscape of water and sci-fi concrete.

A room in New York City that contains 250 cubic yards of dirt worth a million dollars.

This incredible collection of vintage pinball machines can be played at 25 cents a pop.