Claim: Machu Picchu is a core fortified area of a town or city.
Evidence: Machu Picchu -LRB- -LSB- ˈmatʃu ˈpitʃu -RSB- -RRB- -LRB- Machu Pikchu -LSB- ˈmɑtʃu ˈpixtʃu -RSB- -RRB- is a 15th-century Inca citadel situated on a mountain ridge 2430 m above sea level.
A citadel is the core fortified area of a town or city.