Thomas Jefferson's estate is home to hundreds of varieties of historic fruits and vegetables.

This former Cold War missile control site played an important role in the creation of GPS.

The oldest continuously operating fish market in the United States.

A line of blue paint marks the route of the inaugural parade.

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

This mysterious structure by the Washington Monument is a flood barrier designed to protect the White House against rising waters.

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

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

The preamble to the U.S. Constitution written entirely from vanity license plates hangs in the Smithsonian museum.

Architecture lovers won’t stop touching the National Gallery's 19.5 degree marble prow.

A much-maligned monument to teetotalism.

Go take a picture with the inventor of the daguerreotype photographic process.

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

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

During the Industrial Revolution this “Temple of Invention” was full of intricate miniature machines and gadgets.

This 15th-century church houses priceless works of art from a range of Croatian artists.

An ancient Egyptian temple in the middle of Madrid, Spain.

For decades, Puerta del Sol has been illuminated by a giant, guitar-wielding bottle of sherry.

This sweet-toothed bear searching for snacks has been a symbol of Madrid for decades.

This macabre masterpiece of a mural is one of Francisco Goya's "Black Paintings."

A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

A whimsical brother of the nearby Fallen Angel statue takes the falling part quite literally.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

This amazing example of Valencian Art Nouveau looks more like a cathedral than a public market.