Dug as a secret royal escape route, the tunnel became a wartime bomb shelter and dumping ground for vintage cars.

This shining multicolored metro station deep under Naples is said to be the most beautiful in Europe.

The Neapolitan Cult of the Dead still cares for the skulls at this mini-Fontanelle.

This statue is dedicated to the animal cosmonauts that perished during space flight experiments.

This enigmatic artifact remained buried in a churchyard for years.

This charming Latvian lane doubled as Baker Street on the Soviet Union’s version of Sherlock Holmes.

A preserved oak tree about 3,500 years old found in Riga, Latvia.

Latvia's symbolic mountain-shaped national library is home to millions of cultural tomes.

Flamboyant architecture from the turn of 20th century.

3,000 market stands in five former Zeppelin hangars.

Two geological phenomena in one precarious locale: a towering stone window, and a deep blue void.

The medieval home is still engraved with the symbol of the profession, an eye flanked by two axes.

This spectacular dome managed to survive after being bombed in World War II, in an event known as the "Miracle of Mosta."

This prison on the Maltese island of Gozo is almost 500 years old, and they have the graffiti to prove it.

The floor of this spectacular Baroque sanctuary is covered in memento mori.

Burial grounds for more than 1,000 bodies deep under the modern town of Rabat.

This hidden garden boasts amazing views of Lyon.

This abandoned church in central Lyon is missing its front stairs.

The first modern cemetery of Lyon is complete with more than 200 chapels and monuments.

Lyon's "Wall of the Silk Weavers" is one of the largest murals in Europe.

Sky ships, planes, and portraits left as unique tokens of hope and thankfulness.

This historic island prison holds one of the dungeons from the Count of Monte Cristo even though it is a work of fiction.

These quaint French houses dangle precariously over a precipice.

The second-largest natural arch in the Chartreuse Mountains.