A restored Pittsburgh house of God has been converted to a marvelous house of suds.

A toxic ghost town sitting atop a massive coal fire.

The last remnants of Fort Pitt also hold the distinction of being the oldest structure west of the Allegheny Mountains.

There aren't too many operational funiculars around, but Pittsburgh has two!

One of the steepest streets in the United States makes an intriguing challenge for cyclists.

The bank that helped fund the Mexican-American War and the purchase of Alaska met its downfall after helping Augusto Pinochet launder money.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

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

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

A 1,100-ton train fell through the floor in 1953. Workers got it patched up in just 72 hours.

Need a hardcopy of the 50-title Code of Federal Regulations? This is the place.

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

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

An overlooked memorial honoring the local Washington residents who died in World War I.

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

A gorgeous mural outside a beloved D.C. restaurant pays homage to famous Black Americans.

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

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

Architecture lovers won’t stop touching the National Gallery's 19.5 degree marble prow.

A building shaped like the Army Corps of Engineers logo, because why not?

Art deco landmark on the outskirts of Washington, D.C.

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

The remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.

The most accurate timepiece in the world.