The oldest continuously operating fish market in the United States.

Home to items never before seen by the public.

"Congress may voluntarily remain in session throughout the summer, in order that our Congressmen may be protected from the intolerable discomforts and dangers of the ordinary outdoor weather!”

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

Railroad officials in the early 1900s sought to spare travelers the sight of Roman soldiers’ private parts.

Alexander Hamilton’s creation caused quite a bit of controversy.

This elaborate towering structure was once famed for its revolutionary height.

An abandoned network of military bunkers and tunnels open for anyone willing to descend into the darkness.

This sci-fi gazebo located in a Washington power town is made from old bits of industrial electrical equipment.

Cave carved out of a huge snow drift collapsed killing one and injuring five in July 2015.

This statue and its surrounding plaques tells the story of Ko-kwal-alwoot and the kinship between the Samish people and the sea.

This dilapidated ship carcass covered in trees is a striking sight.

An electrifying collection of gadgets and literature from the 16th through 20th centuries.

Former farm staffed by mental patients is now a public park.

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