Machu Picchu is a core fortified area of a town or city.
A citadel is the core fortified area of a town or city . Machu Picchu ( [ ˈmatʃu ˈpitʃu ] ) ( Machu Pikchu [ ˈmɑtʃu ˈpixtʃu ] ) is a 15th-century Inca citadel situated on a mountain ridge 2430 m above sea level .