A rather vulgar example of the transition from Latin to the Italian vernacular.

The engineering wonder and pleasure dome of a much-maligned emperor still holds undiscovered secrets.

Remnants of a 4th-century church with vivid medieval frescoes and ancient sarcophagi hide beneath this old basilica.

Its interior is adorned with some of the best examples of early Christian mosaics.

The underground sanctuary of a mysterious ancient cult.

This curious, round temple is the oldest still-standing marble building in Rome.

This small, ancient Roman temple was once a church dedicated to the patron saint of penitents.

This one-of-a-kind Roman arch is not actually dedicated to the god Janus.

This ancient Roman prison is decorated with an upside-down cross not as blasphemy but as saintly tribute.

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

1513 Turkish world map, full of European state secrets and snarky commentary.

The eclectic home of a leading Turkish architect is a gorgeous piece of eye candy.

Over the centuries, this island paradise has done it all, from providing monks with ecclesiastical respite to sheltering an exiled Leon Trotsky.

One of the largest wooden constructions in Europe was meant to be a casino, but soon became an orphanage.

The only Roman honorific column in Istanbul.

A gorgeous, Gaudí-esque stairway constructed in the city of Istanbul by a prominent Jewish family.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

Hidden beneath a beautiful overlook you’ll find the history of the city depicted in comic strip format next to a pay toilet.

An exquisite collection of fairytale conveyances that puts most car museums to shame.

One man's remarkable private collection of art from around the world.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

This charming candle shop has been in business since 1789.

Entire apothecaries are on display at this Lisbon museum, which explores the history of medicine.

Ring the bell to enter a bar that looks equal parts museum and old curiosity shop.