Akasaka Palace
In 2014, the former Tomioka Silk Mill, Japan's oldest modern model silk reeling factory was designated as the only National Treasure in the category of . Established in 1872 by the government, this is—after the Akasaka Palace—the second modern (post-Meiji) structural National Treasure. The designated property includes several buildings such as the silk reeling mill and the East and West cocoon warehouses.