The Byzantine, pre-Columbian, and medieval art at this stately mansion are some of the most under-appreciated collections in D.C.

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

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

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

A 1,100-ton train fell through the floor in 1953. Workers got it patched up in just 72 hours.

Giftshop catering to cryptozoologists and anyone with a sense of humor.

The district's only illusionarium supports free writing programs for local students with every purchase.

The United States Capitol's former columns still stand.

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

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

An intricately designed junk art house with four extravagant junk art cars hidden in the suburbs.

The world's oldest continuously operating airport was founded by the Wright Brothers.

Walk a trail through a historic Quaker town that outlawed slavery in 1777 and was a major waypoint on the Underground Railroad.

A lawn full of retired spacecraft on display at one of NASA's first research labs.

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

A remote horde of architectural treasures fit for Indiana Jones.

A priceless collection of the Nation's cryptologic history.

An eerie, abandoned military base engulfed by nature and graffiti is now home to a local park.

This lovely tree was a thank you gift from the man known as "Public Enemy No.1."

Ship skeletons haunt Baltimore's waterways.

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.

This free, take-a-book shop seems like a trick but isn't.

The man who first patented the Ouija board rests in peace beneath a headstone that playfully reflects that achievement.

A blank headstone topped with a pile of pennies marks the final resting place of the infamous assassin.