A tiny monument to the unsuccessful attempt by Thomas Jefferson to place the prime meridian in Washington.

Obscure Freemasons still live in D.C.’s largest private residence.

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

Home to items never before seen by the public.

The oldest continuously operating fish market in the United States.

An overlooked memorial honoring the local Washington residents who died in World War I.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

Rumor has it the hot dog stand was targeted by two Russian nuclear missiles.

The Pentagon sits on a former island that was in Virginia at low tide and D.C. at high tide.

The Pentagon is so large that it was planned like a city, complete with internal highway infrastructure.

Please don’t anchor your boat onto the Department of Defense’s underwater data cables.

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

Need a hardcopy of the 50-title Code of Federal Regulations? This is the place.

Art deco landmark on the outskirts of Washington, D.C.

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

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

The United States Capitol's former columns still stand.

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

Walk through the history of American pop culture.

A model home in the Medical Examiner's Office in which grisly death scenes are staged to train forensic investigators.

This bug-eyed water wheel uses the power of the Sun to clean up Baltimore Harbor.

An abandoned church gets a second life as a massive beer hall and event space.

A collection of artifacts from Maryland's maritime past.