Hundreds of prehistoric stones, arranged in perfect lines in a French field.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

A massively oversized measuring tape sculpture sits inside a hidden yard.

Massive puppet-automaton machines created by French artist collective Machines de l’Ile.

This "social palace" housing complex created a relatively stable and self-contained worker's society... for a time.

Spanish architects used seized Muslim gravestones to rebuild parts of the fortress.

Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

A curious carving hides on a marble column in the Mosque-Cathedral of Córdoba.

Spain's largest bullring offers a unique glimpse at architecture and history.

The world's largest wooden structure.

The opulent home that inspired Tintin's Marlinspike Hall and the adventures within.

France's high-tech, future-themed amusement park.

Bordered by forest on three sides and the ocean on the other, the Great Dune of Pilat is the highest sand dune in Europe.

A massive, secret marina for the Nazis' most formidable weapon in the Atlantic.

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

This disused boat elevator was saved from the scrap heap so that visitors could tour its rusting skeleton.

This bunker in northern France was built by Nazi German forces with the intention of launching up to 50 V2 rockets at London each day.

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

Historic medieval fortified city in southwest France.

The world's tallest bridge is also possibly the most elegant.

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

This statue of the great Argentinian car driver is located near a famous curve of the Monaco Grand Prix.

Theme park featuring miniature replicas of European monuments.

Climb inside an iron crystal magnified 165 billion times its normal size.