A floating cat sanctuary on an Amsterdam canal.

The world's oldest Jewish library was founded by Sephardic Jews in 17th century Amsterdam.

This bronze statue of Martin Luther King was placed in the park without permission.

The graveyard is filled with beautiful funerary art and boasts breathtaking views of Florence.

The mummified relic of St. Antoninus.

The largest and most famous wax anatomical collection anywhere in the world.

Overlooked amid the tourist bustle of Florence, this museum is dedicated to the craft of stone inlay.

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

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

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

Twelve natural mummies are displayed in the crypt of this former monastery school.

Frida Kahlo's childhood home, now a museum of her life and works.

Part bookstore, part café, and part forest.

This "City of Books" holds a museum, library, and the complete personal book collections of five of Mexico's greatest thinkers.