Relics of the 1894 Midwinter Exposition continue to delight visitors today.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

The sounds of the world's largest fully functioning pipe organ dazzle shoppers at a Philadelphia Macy's.

This Delaware River bridge is emblazoned with a catty slogan from a more prosperous time.

This strange, big-tailed beast became a Pennsylvania town's unofficial mascot.

The first American department store, and home to the largest operating musical instrument in the world.

Golden and naked, the figure that was once the highest point in New York is all that remains of the second Madison Square Garden.

A pride of the state, this working museum crafts pottery mosaics in the style of Pennsylvania's earliest European settlers.

A daily replay of the experiment that proved the rotation of the Earth.

A local prank turned town icon.

Board a mine car and descend the #190 slope 300 feet underground into the Clark Vein of coal.

This stone tower marks a lookout point over the historic Washington Crossing, and maybe some buried treasure.

This elaborate towering structure was once famed for its revolutionary height.

Yo, Adrian!

The largest university building in the West is a gothic masterpiece containing dozens of theme rooms based on different countries.

This Philly cemetery is the eternal home of many famous area residents, including Rocky Balboa's wife.

Eccentric concrete mansion and museum designed and built by hand from the inside out.

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

Mysterious rocks that ring musically when struck.

A layered tribute to the work of mosaicist Isaiah Zagar.

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

The 2,000-year-old Roman columns are hidden within Barcelona's Gothic Quarter.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.