This Pennsylvania cave holds evidence of the oldest known inhabitants of North America.

This church in Pittsburgh is home to the largest collection of religious relics in North America.

The house that Frank Lloyd Wright "(shook) out of his sleeve at will" at the age of 86.

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

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

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

A small car graveyard sits in the shadow of the famous Cadillac Ranch.

A sculpture made of 10 Cadillacs as a monument to the "Golden Age" of the American automobile.

This constitutionally sound Muffler Man harkens back to the days these attractions were a must-see.

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

The origin of this mechanical boy was a mystery until he revealed his maker by writing it in perfect cursive.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

This Philly landmark has a giant butterfly pavilion, three floors of insect displays, and withstood a $40,000 heist.

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

"We gonna rock down to Electric Avenue, and then we'll take it higher..."

The largest burial mound in the United States holds the remains of prehistoric West Virginians.