This stately mansion, built in 1787 by America's first Secretary of the Navy, is rumored to be one of the most haunted buildings in Washington, DC.

The house where John Wilkes Booth conspired with his co-conspirators.

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

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

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

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

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

A museum cafe showcases Native American dishes and indigenous ingredients from across the Western Hemisphere.

This lonely waterfront memorial to the men of the Titanic was erected by the "Women of America."

Four bald cypress trees in Lafayette Square, across from the White House, mark the southern edge of a 100,000 year old cypress swamp.

One of the oldest train stations still standing in Virginia played a vital role during the Civil War.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

Massive puppet-automaton machines created by French artist collective Machines de l’Ile.

This one-time health resort was used by aristocrats around the world.

This community on a small Venetian island has taken to painting their houses in bright neon hues.

This Venice bookstore has resigned itself to constant flooding by keeping its books in bathtubs and boats.

Two stone columns flank the grand Venice square, but there were supposed to be three.

This Roman statue is missing a limb from when the Venetians stole it from Constantinople during the Crusades.

Go inside to really appreciate this 500-year-old technological masterpiece.

This palatial spiral staircase was so unusual the name "snail" was given to the noble family who built it.

This massive subterranean fissure is known as the "underground Grand Canyon."

A whimsical bridge adorned with decorative dragons.

A petite white lighthouse perched on the ancient core of Stromboli Volcano.

A volcanic old faithful, Stromboli has been erupting continuously for the last 2000 years.