Visitors are treated to a stained glass kaleidoscope interior inside this work of art.

A novel collection of medical curiosities housed in an 18th-century surgeon training academy.

The gilded, masterful astronomical clock will calculate time, dates, and planetary positions for thousands of years to come.

The old observatory in Copenhagen has a spiral corridor used as a racetrack.

Pre-Nazi swastikas adorn the sculpted pachyderms flanking this brewhouse portal.

This sublime architectural marvel is a rare example of an expressionist church.

An ultra-modern diversity park in Denmark has turned an entire city block electric pink.

The ruins of an abbey believed to have been founded by Charlemagne in the 9th century.

Also known as the Square Colosseum, this building is a prime example of fascist-era rationalist architecture.

The first Russian Orthodox church in the Catholic city of Rome in almost a thousand years.

This gallery commissioned by Cardinal Spada is known for its magnificent optical illusion.

This is the oldest Roman-made bridge in the city still existing in its original state.

Rome's ancient Etruscan rival, now a park full of ruins.

The studio built by fascists in the hopes of "reviving the film industry" with the occasional propaganda film opportunity thrown in.

Ancient ruins hidden underneath a modern luxury hotel.

This hydrochronometer was invented by a Dominican monk and is a prime feature in this garden.

This ancient market is often referred to as the oldest shopping mall in the world.

A huge enchanting public park just outside the ancient walls of Rome.

Installed in an act of one-upsmanship, the annual sundial in this church is also a symbolic victory for the Gregorian calendar.

An abandoned Roman salami factory has found new life as an art space home to 200 squatters.

A fairy tale castle in modern Rome.

A forgotten "city of water" underneath the famous Trevi district.

The Pope’s secret escape route.

A Nesting Doll of Churches.