The underground sanctuary of a mysterious ancient cult.

St. Francesca Romana, patron saint of drivers, resides in the church she founded.

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

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

One of several skulls claiming to belong to the beheaded St. John the Baptist is on display at this Roman church.

This former Roman Catholic Church still contains the embalmed hearts and organs of 22 popes.

Architectural monsters are devouring this palace's every door and window.

Museum dedicated to literary greats of the Romantic Period is also the home in which Keats met his untimely end.

The martyr's wax-enhanced skeletal remains lie preserved in a glass case in the Santa Maria della Vittoria in Rome.

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

Where beer lovers can literally immerse themselves in beer.

Celebrating the Eucharist, the day is a legal holiday in many parts of Germany.

The stones of this formerly witch-obsessed castle were used to build a church.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

An existential riddle in the world's largest ancient castle.

The risqué mixed-media sculptures are supposedly a metaphor for Czech politics.

The oldest garden in Prague, once part of an medieval orchard.

This doorless 20th-century elevator doesn't stop or slow down.

An Orwellian sculpture with eyeball cameras watches passersby.

A crucified and bearded female saint.

Increasingly decayed figures stand as a powerful reminder of the human costs of Czech Communism.

One man's personal collection of KGB memorabilia is presented along with his strange viewpoint.

This automated sculpture of two men peeing will spell out text messages with their micturition.

The tunnel's elegant proportions keep you snug with no claustrophobia freak-out.