The celebrated eyesore created by starry-eyed sweethearts.

The site of Austria's biggest concentration camp now honors its victims.

Historic fortifications form the boundary of Vatican City, but it’s not entirely surrounded by walls.

This memorial commemorating fallen Swiss Guards of the French Revolution has been called the saddest stone in the world.

The medieval network of canals hidden underneath the city is opened to explorers each year.

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

This Parisian café sticks almost exclusively to an ethos of reuse.

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

The Pope’s secret escape route.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

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

Collection of skeletal systems from the "world's leading supplier of osteological specimens."

The world’s largest combined collection of U.S. and Russian aircraft got its start in a poultry building.

A rainbow-colored house promotes LGBTQ rights across the street from the Westboro Baptist Church.

Home to Hollywood history and a very special salt crystal.

World's largest precision optical instrument used to detect Einstein's elusive gravity waves.

All that remains of this small town is its mass grave and a myth of a voodoo priestess who predicted its demise.

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

Formerly known as National D-Day Museum, this collection commemorates the battles of Normandy and WWII.

In 2010, Nicolas Cage purchased two plots in this cemetery using one to construct this strange pyramid mausoleum.

This recently restored timepiece has stood all around Kansas City.

Four, 18-foot-tall badminton shuttlecocks lie scattered about the lawn of a Kansas City museum.