Monasteries on rock pillars, once accessible only by frayed ropes.

Jesus' footprints and the first catacombs in the world.

The glowing blue Nymphaeum of Emperor Tiberius.

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

Venice's "Island of the Mad."

Sitting on an Italian hilltop is this surreal fortress built by the mad inventor of electrohomeopathy.

An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

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

As can be expected from a centuries old church built in a canal city, the undercroft of this house of worship is beautifully flooded.

The doodles of a genius line the walls of a secret room under the Medici Chapel, where they were hidden for nearly 500 years.

A large grotto built in the 16th century amidst Florence's famous Boboli gardens.

Thousands of well-dressed mummies below a monastery.

Geothermal waterfalls in Tuscany.

2300-year-old Roman road connecting the empire.

Stalactites and stalagmites in a beautifully lit cave.

According to the local folklore, the myriad colors of this lake are the result of a lovelorn wizard's blunder.

Pompeii's less famous neighbor is still revealing her secrets.

Renaissance villa and gardens complete with a tormented colossus.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

At the crypt of St. Mary of Eulogies and the Dead you are left alone to ponder mortality among piles of skulls.

The underground sanctuary of a mysterious ancient cult.

The middle finger of modernity.

The yawning maw of this pagan visage is said to bite off the hands of liars.

Rome's semi-secret peephole vista is also a former Crusader stronghold.