Secret refuge and museum of the Duke of Florence.

At 207 feet, one of the world's longest continuous escalators.

The first declared National Monument in the United States.

World's first "penitentiary," meant to be humane, drove men insane.

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

An outlandish shoe shaped house built by an eccentric millionaire.

The first of Lancaster's "rural cemeteries."

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.

The remaining relics of the patroness of Paris lie in a chapel under a striking double spiral staircase.

Breathtaking and huge 430 year old maps of Italy.

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