The remains of this ornate chapel now act as a portal to a cramped French cemetery.

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.

A medieval church built into an ancient cave.

A 13th century fortified house built to defend the Duchy of Burgundy.

Immortalized by artists, this church incorporates a medieval lighthouse into its shoreside structure.

A towering baroque basilica jutting out of the French countryside.

A beautiful lighthouse with as many steps as days in the year, as many windows as weeks, and as many levels as months.

Now a memorial, this factory was once used as a concentration camp for artists by the Vichy government.

The remains of this castle, known as the Witch’s Eye, watch over the Thur Valley.

Limestone grottoes turns everyday objects into stone.

A crumbling island fortress that seems to be covered in a field of stone crosses but is simply incomplete.

The eclectic observatory castle of a 19th-century astronomer and explorer.

Personal garden filled with mosaics made of recycled garbage.

Folklore and history carved into Brittany's coast.

An unsettling shrine dedicated to the ravenous beast that prowled 18th-century France.

Remains of the artificial harbours invented for the Allied invasion of Normandy can still be seen at sea.

His "Lionheart" is entombed separately from the rest of his body.

Legend has it this 11th-century castle was paid a visit from the devil.

The castle was reconstructed to fit Kaiser Wilhelm II's romanticized vision of the Middle Ages.

The remaining relics of the patroness of Paris lie in a chapel under a striking double spiral staircase.

This futuristic observatory at the top of the Pyrénées offers unrivaled views.

This collection of French root art looks like an indoor fairy wonderland.

A self-built mosaic house and sculpture park.

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