The city is full of whimsical portals to another world.

The beams of the New College, Oxford dining hall come with an amazing story.

One of the three perfect vellum copies of this historic book known to exist is on display in a specially-designed case.

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

This statue of the "father of television" stands prominently in the United States Capitol.

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.

Coins and medals straight from the mint await visitors to this shop in the nation's capital.

Disks are rolled out onto the south lawn to absorb the impact of Marine One's wheels like giant coffee coasters.

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

This groundbreaking 16th-century map is known as "America's birth certificate."

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

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

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

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

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

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

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

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

The walls of the iconic dome are hollow and have a secret stairway.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

Over 120,000 curious objects that have shaped our modern world.

A community of collapsing homes more than a mile out from the Florida coast.

Former villa and estate of James Deering developed to preserve native tropical forests.

It turns out that a hurricane-prone beach is probably not the best place to house wild animals.