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

An extensive, if one-sided, history of U.S. law enforcement's war on drugs.

The rogue roots are gradually consuming some of the historic marble grave markers.

Bar full of oddities, specimens, artifacts and homages to the great dime museums of the past.

The country's oldest continually-operated mini golf course lies hidden in plain sight, eclipsed by one of D.C.'s most popular tourist attractions.

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

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

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

An obscure public service from the U.S. government that redeems burnt, moldy, and soiled old greenbacks.

The most accurate timepiece in the world.

An atomic bomb-proof strongbox protects the U.S. Constitution from terrorists and thieves.

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

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

During the Industrial Revolution this “Temple of Invention” was full of intricate miniature machines and gadgets.

For 60 years, the academy had no permanent location until members voted Washington D.C. as its forever home.

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

The early data processor factory founded in Washington for the 1890 U.S. Census went on to become IBM.

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

Literal "money laundering."

Where the U.S. government kept its actual treasure, before Fort Knox.

The first presidential bomb shelter was located in an old vault under the Treasury, connected to the White House via tunnel.

The winding route passes through an enclosed alleyway, two tunnels, and leads to the White House basement.

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

Housed in a century-old building, this museum's dedicated not just to soft drinks, but to the free enterprise system.