Explore this medieval cathedral by trying to spot all the malevolent monsters hiding in its beautifully colored windows.

There has been an astronomical clock on this spot since the 14th century.

Visitors dating back to the 1600s carved their marks in the stones of the iconic tower.

In this German city center, the streets have no names.

A small museum dedicated to the history and design of German packaging.

This inconspicuous pharmacy went down in history as the first gas station in the world after fueling the first road trip ever taken.

The first statue to be added to Saint Peter's Square in over 350 years is an ode to migrants and refugees around the world.

An ancient Roman temple first dedicated to an emperor's wife is now a church.

Rome's semi-secret peephole vista is also a former Crusader stronghold.

The "Greatest Sewer" of ancient Rome is one of the oldest sewer systems in the world, and is still in use.

The yawning maw of this pagan visage is said to bite off the hands of liars.

The spot where the fascist dictator made some of his most famous speeches including declaring war on Britain and France.

The remains of this 2nd-century Roman temple are incorporated into a modern building.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

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

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

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

This incredible stone temple is a monument to death, victory, and fantasy architecture.

A Dutch passageway's artistic, aquatic-themed makeover pays tribute to the capital city's famed waterways.

Hidden within a Netherlands crater is a stone bed that lets those who lie in it see the sky as a curved surface.

Unsurprisingly, Holland is home to one of the most magnificent flower gardens in the world.

Science meets wall art to highlight the beauty of famous mathematical equations.

Only a few walls remain of the last church the Pilgrims used before they sailed to North America.

This 11th-century castle sits so low you can't see it behind the surrounding buildings.