The United States’s oldest funicular railway glides up and down a steep Pittsburgh street.

Meet your friends, marry your true love, or tell your enemies to kiss your butt under this historic Pittsburgh timepiece.

Hundreds of protractors affixed to surfaces all over the city.

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

Once the "Eighth Wonder of the World," this iron railroad bridge was decimated by a tornado.

A local prank turned town icon.

"Dark Sky Park" is heaven on Earth for astronomers, one of the rare U.S. locations with no artificial light pollution.

A small granite block at this monument's base is the only part of Lincoln's Tomb outside of Illinois.

Sail through this subterranean show cave that is home to a legend that would go on to name nearly everything around it.