A winding district gerrymandered into the shape of a mantis.

The 320-year-old tree that greeted General Lafayette and rerouted an interstate highway.

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

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.

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

The ruins of this long-abandoned unsuccessful gold mine can still be found.

This ruined quarry once produced the distinctive red sandstone used for construction projects in Washington, D.C.

This abandoned Victorian-style house was built in 1884.

The whole world in one water tank.

Tiny observatory made big contributions to the study of the Earth's motion.

Three abandoned missile silos are hiding in plain sight behind a suburban development in Maryland.

A tribute to the pop culture icon overlooks this Washington D.C. intersection.

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

This robust fence in front of a historic Georgetown home is likely made from hundreds of recycled Revolutionary War firearms.

A historic estate packed with George Washington's heirlooms, and its own nuclear bunker.

A Spiritualist house of worship where believers communicate with the dead in the spirit world.

This stately mansion, built in 1787 by America's first Secretary of the Navy, is rumored to be one of the most haunted buildings in Washington, DC.

A small token of gratitude from freezing cold journalists who were given a warm haven while covering JFK's inauguration.

The early data processor factory founded in Washington for the 1890 U.S. Census went on to become IBM.

America's first federal monument.

This fort down the Potomac from Washington, D.C. was once the only defensive fort protecting the capital.

The school tested mustard gas for the U.S. Army during World War I.

A painfully obvious spy house sits right across the street from the Russian Embassy.

The most accurate timepiece in the world.