The Thirteen Tombs of northwestern --- RECORDSEPARATOR --- Beijing refer to the tombs of the thirteen --- RECORDSEPARATOR --- Ming emperors and empresses. With the --- RECORDSEPARATOR --- imposing views and magnificent structures, --- RECORDSEPARATOR --- they constitute one of the most developed --- RECORDSEPARATOR --- and bestpreserved imperial tombs of ancient --- RECORDSEPARATOR --- China, enclosing an area of 40 square kilo- --- RECORDSEPARATOR --- meters.