Long buried under the 20th-century landscape, this lift lock of the Alexandria Canal is the lone remnant of an ambitious early American transportation project.

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

Rumor has it the uncarved lump behind the three famous suffragists is reserved for the first woman president.

Decades before the scandal, this staircase on the river was a literal "water gate."

The 72-foot giant escaped confinement in a large patch of mulch only to be reburied in the sandy shores of the Potomac River.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

This rare triple-jurisdiction drawbridge passes through Virginia, Maryland, and Washington, D.C.

A former major munitions plant that has been converted into a sprawling art space.

America's first federal monument.

This stately building in Alexandria, Virginia was built by Freemasons to honor one of their most famous members.

A pop-culture attraction outside of Dyersville, Iowa, hits a home run.

This brick-lined pedestrian walkway was once a railway tunnel used during the Civil War.

The romance of early commercial flight still fills this Art Deco destination.

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.

The Kirkland Monument remembers a selfless Civil War hero who braved the battlefield to give water to his dying enemies.

The controversial urban planner who designed Washington, D.C., was buried in Maryland, and can presently be found in Virginia.

Soldiers were buried next to Lee's house in the center of Arlington Cemetery to dissuade the general from reclaiming his property after the war.

This lovely picnic spot featuring thunderous jet landings is an aircraft spotter’s dream.

The graveyard holding the remains of George Washington's slaves was forgotten for nearly 200 years.

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

The oldest continuously operating fish market in the United States.

The national park was once a plantation estate.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.