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

Figures of unknown origin carved into the surfaces of underground caves.

This enormous "cloth of the conquest" depicts the Norman invasion of England in mind-blowing detail.

Tens of thousands of ancient rock carvings hidden in the heart of a French national park.

A 2017 crowdfunding campaign saved this historic castle from being destroyed.

The construction of a tram line unveiled hidden remnants of the old medieval city.

The remains of 40,000 humans, meticulously stacked in a tiny churchyard shed.

One of the largest ochre quarries in the world, hidden in a limestone landscape.

Trek into the depths of the cave where 17,000-year-old paintings exist alongside 400-year-old graffiti.

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

The 16th-century church was kept in its ruined state as a reminder of the casualties of World War I.

A chapel on a volcanic core, marking the end of a successful journey.

An ancient monastery, a locked room, and a mysterious book heist.

A medieval church with largest and oldest collection of Renaissance frescoes in France.

This French castle is said to have once held the Holy Grail but is now a gorgeous mountaintop ruin.

There has been an astronomical clock on this spot since the 14th century.

This medieval tower is all that remains of the castle where Joan of Arc was held before being burned at the stake.

This stunning French estate was so lavish that it landed its original owner in jail for the rest of his life.

These quaint French houses dangle precariously over a precipice.

A well-preserved medieval village nested on a rocky outcrop and surrounded by a network of cliffs, natural bridges and canyons.

A medieval military street hidden beneath a charming French fishing village.

Ivy-covered Medieval tunnels cut through this charming town in France's Loire Valley.

A Gothic cathedral created from volcanic rocks.

Historic medieval fortified city in southwest France.