The oldest Italian café in Boston, this spot also serves as a veritable museum of vintage coffee ephemera.

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.

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

Was there a small "backpack nuke" hidden in the attic? JFK apparently thought so.

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

A bas relief commemorates the "Nuns of the Battlefield" who cared for soldiers on both sides of the conflict.

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

A tiny monument to the unsuccessful attempt by Thomas Jefferson to place the prime meridian in Washington.

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

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

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

D.C.'s first central library was born out of a chance encounter with the philanthropist whose name it bears.

Largest Roman Catholic church in North America.

This imposing Masonic temple a mile from the White House was the first public library in Washington, D.C.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

The oldest of only three existing statues of the great novelist stands in a city he did not care for.

One of Philadelphia's largest murals resides hidden under this bridge.

Alexander Hamilton’s creation caused quite a bit of controversy.

An Irish Memorial commemorating those who perished due to potato blight.

A tour de force of a fountain, memorializing a man who loved fountains more than anything else.

Current docking place of the SS United States, the fastest transatlantic ocean liner.

This once rural mansion now sits in the heart of the city.

This twisty sign depicts the chain's first logo.

At the turn of the century, a chair like rock sat at the top of the falls and hosted the winner of a local beauty contest.