An unusual round church in London with a Templar past.

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

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.

The world's largest collection of witchcraft regalia.

A kaleidoscopic warehouse-maze of handmade neon signs.

The sign at the garden gate reads: "These Plants Can Kill."

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

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

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

Built to be the ideal penitentiary, this abandoned panopticon saw several revolts and even a prisoners' coup.

A founding document of the European Union was written on an island where Roman emperors once banished women.

The sunlight passing through the opening of this huge cave system creates a magical effect.

A small Byzantine church lost in the middle of the mountains of southern Italy.

Buried next to Pompeii, this lesser-known Roman villa was the opulent vacation home of Emperor Nero's wife.

A single column facing the sea is all that's left of one of the most important temples of Magna Graecia.

The tomb of the mythological founder of Padua is not hidden in some obscure crypt, but stands right in the middle of the city square.

Skulls and skeletons are omnipresent in this church dedicated to souls trapped in purgatory.

Tourists to the mountaintop Sicilian town often overlook its ancient fortifications.

Built on a medieval synagogue, this church has a burial crypt, tunnel system, and Jewish ritual bath hiding deep underneath.

A long-buried ancient ruin unearthed right in the middle of the city.

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

Something's missing between the arcades of the Palazzo della Ragione in "the city of the three withouts."

Suffocating dogs was a common spectacle in the fumes of this noxious cave.