High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

Paris' linguistic guide to the international language of, yes, love.

The oldest stone house in Paris was built by its most famous alchemist.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Romans built the world's tallest artificial waterfall in 271 BC.

Secret refuge and museum of the Duke of Florence.

This medieval Italian town is a sheer (and beautiful) cliffside defense.

Eco-village hidden in the foothills of the Alps that created a massive system of psychedelic underground temples.

This shining multicolored metro station deep under Naples is said to be the most beautiful in Europe.

This palatial spiral staircase was so unusual the name "snail" was given to the noble family who built it.

Giant, pink stuffed rabbit on an Italian mountain.

This immaculate and historic water garden culminates in a massive stone dining table with an inset fountain for chilling the wine of the Cardinal's guests.

Natural cathedral designed by Italian artist Giuliano Mauri.

Crushed coral and crystals give the sand its signature coloration.

Go inside to really appreciate this 500-year-old technological masterpiece.

This centuries-old Italian chapel hangs midway down a sheer cliffside.

This giant middle finger statue sends an unambiguous message to Italy's bankers.

The glowing blue Nymphaeum of Emperor Tiberius.

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

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

Stalactites and stalagmites in a beautifully lit cave.

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

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

Renaissance villa and gardens complete with a tormented colossus.