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

The world’s first penitentiary, meant to be humane, drove men insane.

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

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

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

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

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

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!

The first American axe throwing club.

A failed piece of Orientalism has become the proud symbol of a community.

Eccentric concrete mansion and museum designed and built by hand from the inside out.

A pride of the state, this working museum crafts pottery mosaics in the style of Pennsylvania's earliest European settlers.

This historic old movie house was the scene of one of the Blob's most iconic attacks.

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

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

This city square is home to Amsterdam's oldest church and a statue honoring Dutch sex workers.

The attic of a four-century-old canal house hides a clandestine church.

Three connected pink triangles memorialize persecuted gays and lesbians throughout history.

Cozy basement bar sports an inventory of over 2,000 beers.

A little sculpture with a large wardrobe.

This narrow Ghent alleyway is an officially sanctioned street art tunnel.

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

A beer pipeline runs beneath Bruges.