A once-luxurious, now abandoned hotel in the Italian Alps.

Brass cobblestones mark the places where individual Holocaust victims were taken from their homes.

This Italian foot path winds through the mountains via 52 individual tunnels.

Hidden in an Italian forest is a completely homemade amusement park that has taken a lifetime to create.

An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

Venice's "Island of the Mad."

Stalactites and stalagmites in a beautifully lit cave.

A forgotten "city of water" underneath the famous Trevi district.

Pompeii's less famous neighbor is still revealing her secrets.

A beautiful discovery site of prehistoric burials.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

Dancing skeletal figures pay homage to a medieval mural destroyed during World War II.

While you wait to cross the street at a traffic light in Mainz, you might notice that the light is staring back at you.

This natural "sea of stones" was once used by the Romans as a quarry.

Ham is serious business at the Prosciutto Museum-Serious, delicious business.

Those who own or stay at this 500-year-old, allegedly cursed house often meet terrible fates.