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

Indents in the pavement are all that remain from a grisly death machine in Paris.

A surrealist timepiece by the artist of melting clocks.

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

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.

This massive library holds what was once the largest book collection in the world.

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

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

Notorious artist squat renovated into legal studios.

A new sculpture calls attention to climate change in the centuries-old city it threatens.

Thousand-year-old Viking runes adorn an ancient Greek lion at the entrance to the Venetian Arsenal.

A sinister pyramid in the Frari contains the heart of the famous neoclassical sculptor.

Venice's "Island of the Mad."

L. Frank Baum wrote part of the "Wizard of Oz" series in this wooden Victorian beach resort.

Lucha Libre (Mexican Wrestling) themed taco shop.

Shop selling 500 flavors of soda has something for everyone.

America's most famous piece of self-built architecture.

Resting place of Hollywood's immortals is also site of summer film screenings.

Remants of foundations, streets, and streetcar tracks inhabit the cliffs where a landslide occurred in 1929.

Non-profit time travel mart sells goods you would need for a trip through the fourth dimension.

This giant head is all that remains of a once proud statue that survived an earthquake but not a fall off of a wagon.

Faceless white figures loom over the city from the rooftop.

An art supply shop holds the secrets of this quiet neighborhood's raucous Barbary Coast past.

Half of a house.