This famous monument was built in the 17th century. At its gate are wooden doors which are decorated with brass plates fixed with brass nails. Rain and sun strike the doors directly; they have deteriorated to such an extent that if the nails are pulled out, the plates could not be fixed again in the same place. The metal can therefore be treated only on the outer surface, leaving the back surface untreated. See also <i>AATA 12-48. -- AATA