Senators used to relax in the nearly forgotten marble tubs now hidden in the U.S. Capitol Building's basement.

The 28,000-year-old specimen is remarkably intact.

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

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

A museum cafe showcases Native American dishes and indigenous ingredients from across the Western Hemisphere.

This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

Soldiers were buried next to Lee's house in the center of Arlington Cemetery to dissuade the general from reclaiming his property after the war.

Outside the Department of Transportation, a collection of artifacts honors the history of how we get around.

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

This lonely waterfront memorial to the men of the Titanic was erected by the "Women of America."

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

The last of nine massive kilns that produced many of the red bricks for buildings in Washington, D.C. and northern Virginia in the early 20th century.

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

Standing for over 200 years, the abandoned home of a Revolutionary War hero and later a succession of prison superintendents.

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

An 18-mile-long tunnel for sewage waste will soon wind within the bowels of Washington, D.C.

Home to a 27 room house, this estate was crafted by Black entrepreneur Olander Banks Sr.

This grave marks the passing of a historic Jane Doe whose identity remains a mystery to this day.

This brick-lined pedestrian walkway was once a railway tunnel used during the Civil War.

The well-preserved remnants of a bridge that once made up a WW1-era military railroad.

The development and impact of electronic media showcased in a picturesque farmhouse in Maryland.

Dedicated to a U.S. Army lieutenant colonel who was also a bird watcher and artist.

This twice-relocated "Usonian" home is among the smallest built by master architect Frank Lloyd Wright.

Despite its lavish ornamentation, and wholesome lifestyle of its devotees, this mountain commune has faced its share of issues.