The final resting place of the hero of Air Florida Flight 90 known as "the man in the water."

What was once the second largest steel mill in the US is now a sprawling complex of modern ruins.

The final resting place of the world's first nuclear reactor.

Perhaps the most scandalous statue of America's first president.

These recently uncovered walls are all that's left of Washington, D.C's first defense contractor.

This leafy estate is worth $18 million and is so grand it has two mailing addresses.

An Industrial Revolution-era public work that purified water using nothing but sand.

This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

When it opened during the final years of the embargo, all the drinks and cigars were free.

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

The 28,000-year-old specimen is remarkably intact.

A line of blue paint marks the route of the inaugural parade.

Part of a WWII submarine is lurking outside the Washington Navy Yard parking lot.

‘Bush the old fire dog died of poison July 5th, 1869. RIP.’

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

The early data processor factory founded in Washington for the 1890 U.S. Census went on to become IBM.

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

Daredevil repair workers can worm their way out the access hatch, loop ropes over the apex and rappel down the monument.

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

A historic arena where the Beatles played their first concert in the U.S.

A diminutive plaque recalls the treetop sniper who almost killed Abe Lincoln.

The monument's pointy aluminum tip has been melted down by repeated lightning strikes.

A brass plaque dedicated to a convicted cannibal hangs in the National Press Club, and that's not even the craziest part of the story.