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

A secretive collection featuring objects that were designed specifically for U.S. intelligence operations.

The United States Capitol's former columns still stand.

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

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

A historic neighborhood church is reborn as a psychedelic arts collective.

In the basement of the U.S. Capitol Building is a hidden storage room full of ornate floor tiles leftover from the 1850s.

Daredevil repair workers can worm their way out the access hatch, loop ropes over the apex and rappel down the monument.

The hidden offices underneath Memorial Bridge have been locked up since 1976.

The national park was once a plantation estate.

More than 500 unique and specially designed cases collected by D.C.'s "Harmonica Case Man."

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

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

This leafy estate is worth $18 million and is so grand it has two mailing addresses.

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