A historic cemetery filled with quirky faux wood art and unique tombstones.

These abandoned waterworks are crumbling into the Potomac River.

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

Government testing at the asylum briefly explored using marijuana as a "truth serum" on Nazi prisoners of war.

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.

The romance of early commercial flight still fills this Art Deco destination.

Once the supplier for noteworthy projects like the National Cathedral, this old brickworks now lies abandoned.

A clone of a cloned tree that was so important it allegedly had its own guards.

The United States Capitol's former columns still stand.

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

A super-sized promotional trick that is now a D.C. landmark.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

There’s a special club house at the top for the bell ringers.

The towering figures were created from the cemetery's fallen old-growth trees.

A celebrity from the late Cretaceous period.

An Industrial Revolution-era public work that purified water using nothing but sand.

The U.S. Navy’s preposterously detailed mini battleship took 77,000 hours to complete.

One of the largest artillery pieces in the world sits in a Washington D.C. parking lot.

There's a crumbling old mansion inside the Smithsonian National Zoo.

A surprising, but overlooked example of geology in the middle of the nation’s capital.

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

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

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