This unassuming passageway played a key role in one of the most important events in U.S. history.

Over the last century, this elegant columned facade has been home to the headquarters of a bank, several nightclubs, and a restaurant.

This pharmacist and his patient greet visitors to the National Community Pharmacists Association.

The final resting place of an unidentified revolutionary soldier sits behind a Virginia church.

This small pedestal marks the spot of the first lot of land sold in Alexandria, Virginia in 1749.

This unique museum cafeteria showcases the history and regional diversity of African American cuisine.

Look closely and you’ll notice that the color changes a third of the way up the tower.

This mysterious structure by the Washington Monument is a flood barrier designed to protect the White House against rising waters.

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

The little-known, 300-year history of the area includes former lives as a bustling tobacco port, parking lot, and industrial dump.

Before Metro, Washington had a robust streetcar network—and you see the remains of this infrastructure if you know where to look.

The site of the climactic scene from the classic horror film is now a historic landmark.

This cannon dating to 1755 has stood guard at this suburban intersection since 1915.

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

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

At this former Prohibition speakeasy, electric birds signaled the arrival of hooch.

A hidden alley in urban Baltimore is a haven for graffiti artists.

A winding district gerrymandered into the shape of a mantis.

Baltimore's classic clock tower was once topped by a rotating, 20-ton medicine bottle.

Once America's tallest structure, now a Baltimore landmark.

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

The site where Poe "in great distress, and ... in need of immediate assistance" likely died.

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

These wire animal sculptures commemorate the exotic inhabitants that once called the Tower of London home.