They sort through millions of dollars worth of diplomatic gifts on behalf of the government.

A diminutive plaque recalls the treetop sniper who almost killed Abe Lincoln.

This forgotten boat elevator was an engineering marvel in its heyday.

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

This robust fence in front of a historic Georgetown home is likely made from hundreds of recycled Revolutionary War firearms.

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

These recently uncovered walls are all that's left of Washington, D.C's first defense contractor.

A historic ruin just 20 feet away from a busy highway onramp.

Decades before the scandal, this staircase on the river was a literal "water gate."

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

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

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

This sandwich shop has a century-old elevator behind a sheet of plexiglass.

You could be standing at the site of one of D.C.'s most fatal tragedies and not even know it.

The privately owned cemetery that holds room for Washington's finest when they step down from life.

The national park was once a plantation estate.

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

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

When it opened during the final years of the embargo, all the drinks and cigars were free.

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

There’s a hidden military meme engraved on the World War II Memorial.

People escaping slavery may have hidden inside a corpse vault.

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.