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

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

Yo, Adrian!

Mural made of 100,000 pieces of hand blown glass, and until recently, the largest glass mural in the US.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

A daily replay of the experiment that proved the rotation of the Earth.

This elaborate towering structure was once famed for its revolutionary height.

Huge masonic hall in Philadelphia with lavishly themed rooms.

This small New York museum celebrates the mountainous artwork of a Russian mystic.

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

A bit of retro transportation flair preserved in the world's largest department store.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

The "Seinfeld" diner.

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

Once the tallest building in the world and the site of "the highest dinner ever held in New York" this building now holds the most expensive penthouse in the city.

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

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

After a water tower painting was accused of being an ad, a simple fix was made that gave the city a motto.

The Kalamazoo factory has 100 years of instrument-making, and one big wartime secret.

The spaceship-like theater, which is still in use, was one of the most popular exhibits at the 1964 New York World's Fair.

Tour the luxe "glass cage" that inspired and unnerved the architecture world upon its debut.

This elaborate Hindu temple is located in a Chicago suburb, but looks like it was transported directly from India.

First planned industrial community in the United States.