Dr Barnes' $25 billion private collection of art and arboretum.

Huge masonic hall in Philadelphia with lavishly themed rooms.

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

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

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

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.

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

A layered tribute to the work of mosaicist Isaiah Zagar.

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

A museum dedicated to the strange and extravagant costumes and memorabilia of the mummers, a tradition older than Philadelphia itself.

Tour the dark and beloved poet's former cobwebbed basement, which may have inspired "The Black Cat."

Hellam Township is reputed to feature seven remote gates, which when passed through in the right order, open an entrance to hell.

The oldest surviving botanic garden in the United States.

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

A rare view of a preserved Victorian science museum.

The first American axe throwing club.

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

This hidden gem of a garden has one of the only surviving Victorian ferneries in America.

A glittering Thai Buddhist temple in suburban Pennsylvania.

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

One of the world's largest model railroads is a mind-boggling achievement.

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.

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