The perfectly preserved underground rooms where Churchill plotted the war against Germany.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

One of the most well-preserved castles in Italy also contains a rare medieval example of a port fortification.

Italian poet Dante Alighieri is entombed in this small mausoleum in Ravenna, and his hometown of Florence has never been too happy about it.

The small peaceful island off the Venice tourist circuit is where the city began more than 1,500 years ago.

Southern Italy's spinning top village.

Two very green residential towers cleaning the air in one of Europe's most polluted cities.

The secret medieval communication system will whisk your words above the noise of the crowd.

People have been living in the cave houses on this Italian hillside since the Neolithic era.

Renaissance hospital featuring a rotating door into which unwanted babies were dropped.

Italian cave with exceptional acoustics and an unsavory history.

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

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.

A fairytale island floats in the middle of Italy's little-known Lake Orta.

Pilgrimage site for star-crossed lovers.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

Five candy-colored villages on the Italian Riviera.

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

This community on a small Venetian island has taken to painting their houses in bright neon hues.

A medieval church with largest and oldest collection of Renaissance frescoes in France.

Historic medieval fortified city in southwest France.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.