A preserved 18th century homestead in Western Pennsylvania marks the spot where the Whiskey Rebellion began.

A living maritime paradox still floats in the same lake where it was built and resurrected... or was it?

Hidden in the hills of Western Pennsylvania lies one of the best-kept ghost towns in America that you can legally visit.

Designed by Horace Trumbauer in 1893, this Gothic-style castle is now a home for academics.

This colonial mansion has been home to a staggering number of American historic figures.

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

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

Beautiful views of the surrounding hills and birds of prey can be found at this sanctuary.

Sections of the iconic limestone columns have been left uncleaned as a reminder of the city's polluted past.

Narrow gorges and deep pools created by long-ago glaciers.

The final resting place of two members of the infamous Doan gang, notorious outlaws and Revolutionary War Loyalists.

An otherwise quiet campground becomes a bustling medieval town for two weeks every year.

Inside this 150-year-old barn turned antique shop is a vast array of items for curios hunters.

Don't get it twisted: This is the oldest pretzel bakery in the United States.

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

The Cold War-era "underground Pentagon" is a sprawling subterranean hideaway for the Defense Department.

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 planned settlement in Pennsylvania once housed the aristocratic refugees of the French Revolution.

An occult-y, historic hotel with the World's Largest Ouija board on the roof.

An Irish Memorial commemorating those who perished due to potato blight.

What looks like a simple quaint estate in rural Pennsylvania was in the 18th century home to a small monastic community.

One of the oldest log cabins in America is one of the last of its kind this historic Swedish dwelling remains a piece of living history.

A retired firefighter created this contraption so he and his family wouldn't die if accidentally buried alive.

This shop filled with oddities and knick-knacks is named for a 19th-century charlatan.