The span is crooked and made from two older recycled bridges.

Washington's top-secret Cold War-era doomsday communications tower is located in a small neighborhood park.

The only Civil War battle in Washington D.C. took place near this highest natural point in the city.

Surrounded by traditional homes, this Tolkien-esque dwelling stands out on a quiet street in suburban Maryland.

A striking, menacing sandstone peak towering above a landscape that's equal parts Mordor and the Moon.

This outsider art paradise is filled with dinosaur sculptures crafted from recycled machinery.

The final resting place of two (or three) presidents, one vampire, and 18,000 Confederate soldiers.

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

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

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

The national park was once a plantation estate.

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

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

The system of air guns are fired off remotely to scare any trespassing avians.

A derelict bit of transportation infrastructure hidden in the woods.

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.

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

A portal into the bricked up canal that runs through the heart of Washington D.C.

This seemingly out-of-place gas station by the Watergate hotel was once described as the most expensive gas station in the world.

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

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

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

On the Fourth of July this area will transform into a Pompeii-like storm of falling embers and ash.