This 19th century machine put animals (including humans) in boxes to study how they metabolized calories.

One of the first commercially successful anthracite-powered iron-making operations in North America.

The slate extracted from these Pennsylvania quarries was once hailed as the finest in the world.

This decommissioned surface-to-surface missile resides outside the American Legion Post in Pennslyvania.

True to his word, George Swanson is buried in his white 1984 Corvette.

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

Francis Julius LeMoyne built this crematory in 1876; he was the third person to be cremated here.

The god of wine stares out at passersby on this busy Pittsburgh thoroughfare.

The beloved, war-tested mascot of a Union regiment graces their battlefield monument.

An ode to filmmaker George A. Romero, who used the mall to film an iconic horror movie.

Color-coded signs direct drivers on a network of routes designed to avoid Pittsburgh traffic.

In the parking lot of a fast food restaurant, a statue memorializing a prolific bull elephant.

The last remnants of Fort Pitt also hold the distinction of being the oldest structure west of the Allegheny Mountains.

In this cemetery stands the country's first public crematorium.

The Pennsylvania shopping center was once the setting for the 1978 film, "Dawn of the Dead."

This 15-foot tall obelisk commemorating the Philadelphia-Baltimore railroad connection sat neglected for over a century.

This massive sycamore tree has been labeled as one of the largest in the state.

This historic furnace was once used to produce cannonballs during the Civil War.

The only statue of its kind to commemorate Washington's beginnings as an officer of the British Colonial Militia.

Frank Lloyd Wright built this suburban synagogue late in life, but it stands among his most iconic masterpieces.

Old neon signs from the City of Brotherly Love provide a snapshot of the city’s evolution.

A portion of the old Pirates stadium over which a defining home run once flew still stands even after the rest of the stadium was torn down.

The largest clock face in the United States is twice the size of Big Ben and infinitely more ad-sponsored.

This stately 19th century library pushed architectural boundaries at a time when the public library movement was just taking off.