The famous facade of Grand Central Terminal hides a regulation tennis court, and it's not the first one.

Once considered the height of medical modernity, this structure is now the oldest remaining component of Roosevelt Hospital.

The former home of the reclusive "Weird Wendels" who dominated New York real estate a century before Donald Trump.

A miniature rainforest is growing inside of a Midtown Manhattan office building.

This abandoned subway station beneath the Waldorf-Astoria hotel is allegedly used to secretly transport presidents.

NYC's legendary underground network for bovine transportation.

The beautiful tunnel that ran from the lobby to Penn Station is still hidden underneath 34th Street.

This New York holdover was built to provide housing for shopgirls and still does not allow men above the lobby.

A dark patch of the ceiling at Grand Central Terminal which was not restored is still stained brown by tobacco.

Giant instrument-shaped home in Fayetteville, Georgia.

On a quiet suburban street stands a peculiarly decorated house covered in mosaics.

A wacky two-story folk-art assemblage of carved and found objects, with lights, motion, and sound now in need of financial support.

A reclusive Memphis neighborhood is home to decades worth of misunderstood Masonic folk art.

This structure among the trees was the result of divine inspiration.

This iconic science fiction house still looks like something from the future.

The ghostly remains of an accidental sea.

The final resting place of one of the United States's greatest poets.

These rose marble urinals are the most luxurious loos in Liverpool.

The tallest mud-brick structure in the world has been standing since the 1500s.

New York's oldest magic store.

London's largest outsider art museum.

A WWI fighter plane and turn-of-the-century penny candy shop are among the unexpected features of this Financial District building.

This retro diner claims to be the birthplace of poutine.

Travel back in time at a Moroccan-inspired restaurant that was the height of glamor in the 1970s.