This huge, disused viaduct is now a crumbling concrete underworld of covered in years of graffiti.

This lush forest valley was once mined for lumber to the extent that it was once nicknamed "The Pennsylvania Desert."

Once the world's largest reinforced concrete structure, this abandoned bridge now beckons urban explorers.

The graffitied ruins stand hidden within the Pennsylvania woods.

House of vintage taxidermy and Steampunk sculptures in a quiet Pittsburgh neighborhood.

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

Mysterious rocks that ring musically when struck.

A smaller model of the Da Vinci sculpture that took 500 years to come to life.