Secret refuge and museum of the Duke of Florence.

The oldest operating pharmacy in the world features 800-year-old recipes.

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

Renaissance hospital featuring a rotating door into which unwanted babies were dropped.

Geometry and mystery come together in an epic show of octagonal masonry.

These tombs were built into the side of a mountain so that ancient angels could reach the dead.

Hear the quietest sound from across the dome.

Breathtaking and huge 430 year old maps of Italy.

The incorrupt tongue of the patron saint of lost things is venerated in this basilica.

105-foot wide giant metallic flower blooms anew every day in the heart of Buenos Aires.

A beautiful young girl said to have been buried alive in her coffin…

Buenos Aires' city of the dead contains some very famous remains, including Eva Perón.

This historic, palatial theater is now one of the world’s most beautiful bookstores.

A gateway to a mysterious network of underground tunnels.

A marvel of Byzantine engineering under the streets of Istanbul.

Even France's favorite aquatic son Jacques Cousteau, couldn't get to the bottom of it.

A fountain standing as a testament to a doomed alliance.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

Charnel house at the foot of Mount Sinai.

Home to Alan Turing, the cracking of the Enigma code, and Captain Ridley's shooting party.

Once close to extinction, there is no shortage of elephant seals on the beaches of Año Nuevo State Park.

One of the most scenic stretches of road in America winds between some of the country's oldest trees.

An 18th-century Spanish watchtower made entirely of seashell and concrete.