The last of Philadelphia's wood-paved streets is now a landmark of terrible engineering.

In the bowels of a 19th-century brewery lurks a fine-dining restaurant offering an array of themed feasts.

America's smallest national park site is the former residence of exiled Polish national hero Thaddeus Kosciuszko.

A tiny, unmarked beer and whiskey bar above an Ethiopian restaurant in West Philly fails to conceal live bluegrass.

For decades, it has disappeared and reappeared as water levels rise and fall.

The humble field where the first Major League Baseball game was played.

Where the oil industry began.

Pittsburgh's literal underground railroad.

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

A glittering Thai Buddhist temple in suburban Pennsylvania.

Steepest flood safety railway in the entire world.

Built in 1931, this small passageway is believed to be the first modern skyway.

Thousands of people walk over this fantastic work of art every day, but how many notice it?

A 115-year-old restored German dining hall awaits those who venture beneath the Minnesota State Capitol.

These curious caverns have been home to mushrooms, gangsters, and disco.

Driftwood dinosaurs lurk within trees covered in a rainbow array of avian abodes.

This 38-drawer structure claims the superlative title, but it isn't the world's only giant filing cabinet.

Tour the world's largest deep-hole dimension granite quarry, where you can view the plant where gravestones are made and roll a ball down the outdoor granite bowling alley.

This historic mini-suspension bridge was swept away once but is now here to stay.

These towering spires and glowing walls are carefully crafted from hundreds of thousands of icicles.

This narrow canyon has been carved by the river over thousands of years into spectacular and curious forms.

Even Henry David Thoreau found this glacial pothole irresistible.

Ruins of the elaborate house where the enigmatic costume designer threw glamorous parties for New York's theatrical elite.

After giving up Michelin glamour for his Amish faith, one chef now makes stellar sausages in a small, off-the-grid shop.