Chicago's Navy Pier on Lake Michigan was a training hub for aircraft carrier pilots during WWII.

Fragments of architectural wonders from around the globe are embedded in the newspaper building's walls.

A display of magnificent stained glass windows is the first exhibit of its kind.

Years of archaeology, just chillin' by the water cooler.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

The twin towers in this Chicago fountain use 50 foot tall video screens to spit on people.

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

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

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

The grand marble structure next to the White House is Andrew Carnegie's temple to Pan-American diplomacy.

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.

At 207 feet, one of the world's longest continuous escalators.

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

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

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

Every drop of D.C. tap water flows through this old waterworks.

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

Washington's iconic carousel has a nice piece of Civil Rights history.

Legend has it that President Grant’s frequent drinking in the lobby gave rise to the term “lobbyist.”

The most accurate timepiece in the world.

A historic ruin just 20 feet away from a busy highway onramp.

The "lovely red Vega" of the legendary record-settling pilot.

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

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