Each of these hand-painted wooden boxes, which date to between the 16th and 19th centuries, contains a genuine human skull.

A bibliophile's heaven that contains hundreds of bookstores, offering over a third of secondhand books for sale in Tokyo.

A century-old church is now a space museum with a treasure trove of Soviet space items.

A micro-communist utopia in Spain with no police, no mortgages and full employment.

A collection of grotesques lines the walls of this Italian villa.

142 ceramic steps become a mosaic once a year.

A madman's personal garden filled with 1,000 sculpted heads.

Thousands of well-dressed mummies below a monastery.

Behind medieval walls in a corner of bustling Palermo is a breathtaking former mosque once inhabited by a wolf-taming hermit.

This uncanny fresco celebrating the "triumph of death" was split into four pieces to be moved to another museum.

This skeletal, unfinished Gothic church once housed a miraculous masterpiece by Raphael.

The world's most active stratovolcano is almost always erupting.

A 16th-century horror show built in a lovely Italian garden.

When occupying Nazi troops detonated a mine below, medieval frescoes were revealed in this small cliff-side hermitage.

This picturesque Umbrian city has a subterranean side that has long remained hidden.

Nine caves filled with recently-discovered archaeological finds under the houses and the streets of the most ancient district of an old town.

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

This domed temple was built in a hidden cave mouth as a refuge for sinners seeking absolution.

The bright red cars take travelers through breathtaking Tuscan scenery.

On rare days, this abandoned castle's gatekeepers open its doors, revealing the eye-popping splendor hidden inside.

Renaissance villa and gardens complete with a tormented colossus.

An extraordinary house museum and cabinet of curiosities in the heart of Florence.

An incredible menagerie of more than 3 million taxidermied animals at the oldest science museum in Europe.

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