A musical instrument played by the sea.

One of the best-preserved Roman amphitheaters is still used today, but for less brutal events.

A spherical "micro-nation" in the heart of Vienna.

Op-art architecture designed for happiness.

This former insane asylum now holds a pathological anatomy museum.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

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

What looks like a crashed Zeppelin is actually a bright, airy reading room perched atop a modern museum.

This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

Hamburgers are intensely proud of their tunnel beneath the river.

The small alleys in Lübeck's Old Town are a result of medieval urban sprawl.

A tilted half-timbered house from 1672 is built into a salvaged segment of a medieval wall.

The most iconic structure in Scotland has been home to bishops, colonels, and Sean Connery characters.

An ancient Scottish rock formation said to be the gravesite of a giant remains ensconced in legend and intrigue.

An 18th-century lighthouse built on a 16th-century castle is now a monument to the maritime beacons of Scotland.

The ruins of this gorgeous clifftop castle look like something from a fantasy novel.

One of the most easily accessible examples of the rare 1960s UFO houses.

This riverside restaurant has been serving customers since 1146.

This strange sculpture depicts a giant nightmare hare crushing a man to death beneath its colossal bulk.

This abandoned coliseum was intended to be a grand Nazi rallying ground before it was halted at the end of the war.

Remnants of the most densely packed city in world history, that thrived on anarchy for 30 years.

Singapore's landscaping project is home to 18 incredible Supertrees.

The largest tea plantation in Southeast Asia supplies gorgeous vistas alongside tea for the surrounding countries.

Once the private home of China’s most legendary tycoon, getting inside this stunning mansion no longer requires an elite pedigree or acts of daring.