One of the world's tallest Ferris wheels takes visitors high above Las Vegas in a spinning party room.

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

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

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

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

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

A portal into the bricked up canal that runs through the heart of Washington D.C.

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

This lovely pocket park is one of the most under appreciated in D.C.

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

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

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

Rumor has it the uncarved lump behind the three famous suffragists is reserved for the first woman president.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

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

Largest Roman Catholic church in North America.

Home to items never before seen by the public.

This cemetery has graves dating back to the 17th century, including the city's oldest carved tombstone and an ominous cryptogram.

Unrepaired walls from a 1920 anarchist bomb attack.

Years of archaeology, just chillin' by the water cooler.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

A typical "Old South" manor, once owned by author Anne Rice, served as the setting for several of her witchcraft sagas.

A small park on Bourbon Street features life-size bronze statues of New Orleans musicians.