More than 20 years ago, a community of men and women in the French region of Burgundy set themselves a massive challenge: to build a castle using the techniques of the Middle Ages. The site in the town of Guédelon is open to visitors, offering them an immersion into the 13th century. Today, nearly 40 people work every day on this medieval construction site. Stone quarrying is the first step in building a castle. And to transport the stones to the site, modern machines are banned: everything is done like in the 13th century, with horsepower.