The "Seinfeld" diner.

Mysterious 500-year-old tapestries depict a unicorn hunt.

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

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

Elevated freight railway turned wildly successful urban park.

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

One of New Jersey's oldest surviving buildings still bears the mark of our former British overlords.

Century-old shop, specializing in Occult products.

This extraordinary Depression-era expenditure was modeled after a postcard of a Mediterranean hotel.

Frank Lloyd Wright built this suburban synagogue late in life, but it stands among his most iconic masterpieces.

This Delaware River bridge is emblazoned with a catty slogan from a more prosperous time.

A tour de force of a fountain, memorializing a man who loved fountains more than anything else.

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

Erected in 1697 this Philadelphia bridge is the oldest surviving roadway bridge and perhaps the oldest stone bridge in the United States.

The sounds of the world's largest fully functioning pipe organ dazzle shoppers at a Philadelphia Macy's.

This little-known Revolutionary War fort is supposedly haunted by the ghosts of its past.

A field of nothing but boulders which resembles a giant's gravel driveway.

The fastest transatlantic ocean liner sat abandoned in a Philadelphia shipyard for decades.

This stone tower marks a lookout point over the historic Washington Crossing, and maybe some buried treasure.

A local prank turned town icon.

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

Ant sculptures march up the side of what used to be an iconic spot in punk rock lore.

A mine fire has been burning under the deserted town since 1962, but this church is still going strong.

Yo, Adrian!