New York's oldest and possibly grandest keeper of books.

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

New York City's smallest piece of private property.

This massive subterranean fissure is known as the "underground Grand Canyon."

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

In Florence's great Duomo, a 26 foot fresco honors a mercenary famous for attacking Florence.

An extensive collection of reliquaries containing the bones of saints housed in the largest Catholic church in Venice.

A lover's walk between hilltop towns, decorated with graffiti love notes.

Small on the outside, big on the inside, this church is an astonishing act of visual deception.

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

Secret refuge and museum of the Duke of Florence.

The bomb-ravaged remains of of a colossal Neptune.

Five candy-colored villages on the Italian Riviera.

The famous sculptor left his mark on this Italian wall in an internationally protected example of street art.

Over 50 exquisite hand-painted Renaissance maps decorate a Medici storage room.

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

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

The middle finger of modernity.

This Venice bookstore has resigned itself to constant flooding by keeping its books in bathtubs and boats.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

Where commuters walk through remnants of an ancient Greek necropolis.

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

The hallucinogenic center of the ancient world.

A Bronze age settlement on the Greek island of Santorini might have been the inspiration for Plato's Atlantis.