Stone age urban planning.

Imperial palace of Emperor Galerius, the Emperor behind the worst Christian persecutions during the Roman Empire.

An apparition of Virgin Mary in Herzegovina.

Holy Grotto of Montserrat Monastery holds one of Europe's mysterious black Madonnas.

A striking symbol of the Bulgarian capital.

Beautiful Austrian natural history museum with carved ceilings and row after row of ancient taxidermy.

Controversial site of what could be Europe's first pyramid.

An underground city of salt.

Structure built from the skulls of vanquished foes.

Giant eggs, walls of bread, and nightmare surreality mark the largest collection of works by Salvador Dalí.

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

Flamboyant architecture from the turn of 20th century.

This small Estonian hill is covered in hand-made twig crosses that are said to bring good luck.

Two large posteriors in one giant statue.

A church of bones, decorated with 40,000 human skeletons.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Lady Liberty's original designer installed a little clone in this French fountain.

This ancient theater was once the home of fierce gladiatorial battles.

A colorful piece of contemporary art cheerfully clashes with Lyon's historical architecture.

The world's largest reflecting pool is just two centimeters deep.

This ancient Roman bridge and aqueduct still stands as a wonder of classical construction.

France's most famous cemetery, with some of its most curious tombs.

A little sculpture with a large wardrobe.

After the famous composer died in Paris, his sister snuck his heart out of the country to honor his wish that it be buried in their native country.