The world-record holder for the longest bridge stretching continuously over water.

"Congress may voluntarily remain in session throughout the summer, in order that our Congressmen may be protected from the intolerable discomforts and dangers of the ordinary outdoor weather!”

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

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

The only place for a truly presidential dram.

D.C. once had its own tiny rival to the New York Stock Exchange.

A muscular Art Deco monument represents the struggle between regulators and unbridled markets.

One of the most influential presidents in U.S. history wanted only this plain, elegant monument as his lasting memorial.

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

The oldest operational cathedral in the U.S. has one shell of a way of projecting speakers' voices.

This cathedral dedicated to Louis IX, sainted King of France, holds many secrets.

Shop for books in the New Orleans house where William Faulkner once lived.

This macabre shop, filled with art, oddities, and taxidermy is hidden in the heart of the French Quarter.

The winding route passes through an enclosed alleyway, two tunnels, and leads to the White House basement.

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

A spectacular tribute to statesman and philanthropist Andrew Mellon.

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

This taxidermy horse was a Civil War hero.

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

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

There’s a hidden military meme engraved on the World War II Memorial.

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

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