Op-art architecture designed for happiness.

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

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

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

A stone from Africa's tallest peak is immortalized in a Potsdam palace—but is it actually the mountaintop?

One of the world's largest ancient burial mounds.

A multi-story, retro videogame time capsule in the Netherlands.

This small monument marks the divide between the Atlantic and Indian Oceans at the southernmost tip of Africa.

This smaller cousin of the Forbidden City has gone from ancestral sacrifice to tourist's whispers.

Where George Lemaître discovered the expanding nature of the universe.

The Lund University's former gym houses a museum focusing on the creative process of art.

A monumental toilet that is also host to rare plants.

This 19th-century zoological collection has withstood the test of time.

An installation that makes understanding the size of the universe a walk in the park.

Though they might seem like arbitrary scratches in the wall, these were once official measures of length.

The Belgian library displays burned books that were salvaged from the fires of both world wars.

Above the door of a house, a plaque claims to commemorate the future living place of the inventor of time travel.

An imperial church bombed to ruins during WWII now stands as a jagged memorial.

A unique look into the bowels of a century-old funicular.

The world's first clock to use set theory as a measure of time required the invention of a new light bulb just to maintain its obtuse measurements.

An astonishingly accurate water clock that doubles as an hourly spectacle in this Berlin shopping area.

This Netherlands museum holds a gloriously mechanical collection of ornate musical automata.

A 30-foot-high stream of chocolate flows continuously at the Lindt Home of Chocolate.

This former cigarette factory was built in a style inspired by Islamic architecture.