A wrecked ship dating back to the American Revolution was only recently discovered off the Delaware coast.

What began as an art installation is now the private drinkhaüs for a brewery's employees.

The stone marker that Mason and Dixon placed at the eastern end of the famous north-south border they surveyed.

This palatial botanical garden is home to one of the largest pipe organs ever installed in a private residence, and a piece of Wood's cycad.

This dig site outside D.C. is known for its exceptionally high density of baby dinosaur fossils and dinosaur eggs.

A lovely aquatic park built by a one-armed Civil War veteran who made a fortune from lotuses.

A Civil War fort in the middle of Washington, D.C. has been swallowed by a forest.

Enormous piles of historically significant stones, dumped by Congress in a forest, and abandoned for 60 years.

A derelict bit of transportation infrastructure hidden in the woods.

A historic estate packed with George Washington's heirlooms, and its own nuclear bunker.

The famous abolitionist’s preserved estate is one of Washington's finest monuments to its great Black citizens.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

This grand gothic brewery has been pumping out suds for over a hundred years.

"Congress may voluntarily remain in session throughout the summer, in order that our Congressmen may be protected from the intolerable discomforts and dangers of the ordinary outdoor weather!”