Surrounded by industrial sprawl, a small monument marks the site of William Penn's first landing in Pennsylvania.

North America's oldest quarantine facility was built in response to Philadelphia's 1793 yellow fever outbreak.

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

Descendants of this colonial Pennsylvania family still travel from far and wide to visit the 300-year-old home of their Quaker ancestors.

A rural colonial settlement that contains the remains of a store and cooper.

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

The mounds at this site were reconstructed with the help of archaeologists and historians.

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.

This suburban house is made of dirt, and almost sparked a revolution in home construction.

The bridge's highly-contested plaque (once again) honors Confederate President Jefferson Davis.

One of the oldest standing structures in Montgomery County, Maryland.

The ruins of this long-abandoned unsuccessful gold mine can still be found.

The local community brought back this land to transform it into a nature preserve.

A quick journey through the history of Annapolis.

This memorial honors five journalists who were killed in a mass shooting in 2018, and affirms the importance of the first amendment.

A total of 14 men held the title of "president" before George Washington—their historical legacies are enshrined in the lobby of a hotel.

This 16-foot, intricately detailed model of the Gearing-class destroyer has been called the most detailed model ship ever built.

This spot memorializes one of the greatest plays in NFL history, unless you happen to be a Raiders fan.

Live chainsaw carvings of tiki statues aim to keep a tradition with ancient roots alive in this small Delaware town.

A drab two-story office space in Delaware is a hidden tax haven for Hillary Clinton, Donald Trump, and over half the Fortune 500 companies.

In 1787, a group of delegates met at this very spot to drink, be merry, and ratify the Constitution of the United States.

The Dover International Speedway is home to a towering, concrete-skinned, racecar-hungry behemoth.

Enchanting gardens surround a derelict mansion, all hidden in plain sight behind a stone wall.

The tombstone of the founder of the lost town of Ogletown is now stuck inside a traffic median.