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

Golden and naked, the figure that was once the highest point in New York is all that remains of the second Madison Square Garden.

Yo, Adrian!

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

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

A layered tribute to the work of mosaicist Isaiah Zagar.

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

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

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

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

This little-known collection holds everything from "Dracula" notes, to the manuscript of "Ulysses," to the forged works of Shakespeare.

South Philadelphia is home to Keith Haring's only surviving in situ collaborative public mural.

The world's third-largest crystal sphere has sat in the Penn Museum since 1927 with the exception of one outlandish theft.

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

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.

A beloved horticultural oasis on the grounds of a wealthy family's former estate.

The remains of an old sawmill, gristmill and the surrounding industry dating back to the 18th century.

This Great Depression-era creation was once known as the strangest house in the world.

In the woods of New Jersey lie the ruins of a munitions village abandoned after World War I and the remnants of a 1920s wooden racetrack.

The first partially complete dinosaur skeleton was discovered here, forever changing the world's view of the ruling reptiles.

This splendid Versailles-inspired mansion has the largest French-style formal gardens in North America.

Come for the Italian food, stay for the taxidermy and giant statues.

A desiccated merman and a walrus penis bone are among the oddities in this eclectic collection of shipwreck treasures.

Captain John Smith thought these cliffs were amazing in 1608 but sharks thought so 20 million years before him.