Workers using medieval tools and techniques have completed most of Guédelon Castle in Treigny, France. The castle attracts around 300,000 visitors annually to watch its construction and learn about traditional craftsmanship. The project, which began in 1990, is led by Jacques Naegelen, a French historian and architect. Visitors can observe stoneworkers, blacksmiths, and carpenters at work, as well as participate in workshops and demonstrations.