Rennes-le-Château

 was a castle in Southern France.

At some point, the castle was destroyed, and the Knights Templar rebuilt it on the same location. Shortly after, in the late 16th century, the Revelation Sect finished off the exterior.

River Song and Helen Sinclair visited the castle in the 17th century, while searching for the eighth piece of the Doomsday Chronometer. They intentionally arrived a week after the secret doors and passages had been added. (AUDIO: The Doomsday Chronometer)