World War II bunker still standing on the New Jersey beach.

Invading U.S. troops were first seen from this now-abandoned tower, leading to the Spanish-American War.

The world's second largest single-dish radio telescope, once used to contact E.T.

This historic lighthouse was well known for the large number of women who served as its keeper.

Mysterious rocks that ring musically when struck.

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

A unique sculpture park that specializes in the huge and bizarre.

One of the oldest log cabins in America is one of the last of its kind this historic Swedish dwelling remains a piece of living history.

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

The first American axe throwing club.

Instruments, apparatus, and rare books all relating to chemistry and its related sciences.

One of the oldest of its kind.

The corporeal remains of Napoleon III's dentist rest under this 15-story obelisk.

The first American department store, and home to the largest operating musical instrument in the world.

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

This beloved marketplace mascot poops money and grants good luck.

The abandoned coal loading dock is a canvas for unsanctioned art.

Enjoy a slice while browsing the world's largest collection of pizza memorabilia.

Where America's first doomsday cult awaited the end of the world.

Philadelphia boasts one of the best — and most often overlooked — traditional Japanese gardens in North America.

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

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

Step inside Lucy, the world's largest "elephant."

The oldest active church in Pennsylvania is also the second oldest Swedish Church in the United States.