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

First a horse rendering plant, then a 19th century landfill, this beach is full of glass from thousands upon thousands of broken bottles.

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

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

A playground inspired by differential calculus dangles from the ceiling of the Liberty Science Center.

The rusting remains are visible sticking out of the waters of the Delaware Bay.

A recently abandoned psych ward at the end of Sanatorium Road.

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

Board a mine car and descend the #190 slope 300 feet underground into the Clark Vein of coal.

Once the world's largest reinforced concrete structure, this abandoned bridge now beckons urban explorers.

This park contains a number of standing stones meant to heal and inspire.

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 castle still holds traces of the abandoned Roman fort it was built atop.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

Tucked behind New Jersey's abandoned Gingerbread Castle lie the eerie ruins of a once-flourishing paper mill.

One of the oldest of its kind.

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

Lehigh Valley barge No. 79 still gets tugged along - but now it houses a museum and unusual performances.

Current docking place of the SS United States, the fastest transatlantic ocean liner.

A clone-tree in Washington Square Park sprung from seeds that went to the Moon and back.

The famous bell was secreted away and hidden in a church in Allentown during the British occupation of Philadelphia.

The remains of a community that was forced to move for a dam that never materialized still rot in this Pennsylvania park.