Largest Roman Catholic church in North America.

This historic building is now home to the Public Access Corporation for the District of Columbia.

Home to two notable early-20th-century Black educators, Lucy Slowe and Mary Burrill.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

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

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

The United States Capitol's former columns still stand.

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

Once used by British troops to gather water prior to the Battle of Bladensburg.

A lovely aquatic park built by a one-armed Civil War veteran who made a fortune from lotuses.

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

A super-sized promotional trick that is now a D.C. landmark.

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.

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

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

The national park was once a plantation estate.

The only National Monument ever to go missing for nearly 50 years then resurface in a dump.

The country's oldest continually-operated mini golf course lies hidden in plain sight, eclipsed by one of D.C.'s most popular tourist attractions.

John Tyler never got to be buried at his beloved home, but every pet his family owned since has been.

Nine of the very few concrete ships ever made in the U.S. are beautifully decaying off a Virginia pier.

Eat first, shop later at this eatery within an Asian grocer.

A unique columnar residence built in the 19th century.

Rising 30 feet in the air atop Quarry Hill, the Old Powder House is the oldest stone building in the state of Massachusetts.