The video game-themed street art first popped up in the French city.

Former hunting lodge of a duke who was an avid collector of impressionist works.

This structure atop a craggy cliff in one of the most beautiful parks in Paris boasts an unbeatable view.

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

A favorite Paris bar for U.S. expats, including Gershwin, Hemingway, and James Bond.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

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

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

Vienna's diversity-themed traffic lights were inspired by the Eurovision Song Contest.

The solemn exterior conceals an opulent interior of this 17th century church.

Beautiful Austrian natural history museum with carved ceilings and row after row of ancient taxidermy.

Baroque celebration of the end of the Great Plague of Vienna.

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

The former private quarters and office of Dr. Sigmund Freud now hosts a museum housing the works of the founding father of psychoanalysis.

The final resting place for the remains of 143 Habsburg royalty.

The beautiful baroque library of the Hapsburg empire.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

America's Most Wanted's set resides in this tribute to the history of crime and punishment.

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

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.