Bangladeshis (Bengali: বাংলাদেশী [ˈbaŋladeʃi]) are the citizens of Bangladesh, a South Asian country centered on the transnational historical region of Bengal along the eponymous bay. Bangladeshi citizenship was formed in 1971, when the permanent residents of the former East Pakistan were transformed into citizens of a new republic. Bangladesh is the world's eighth most populous nation. The vast majority of Bangladeshis are ethnolingustically Bengalis, an Indo-Aryan people who are predominantly Muslim. The population of Bangladesh is concentrated in the fertile Bengal delta, which has been the center of urban and agrarian civilizations for millennia. The country's highlands, including the Chittagong Hill Tracts and parts of the Sylhet Division, are home to various tribal minorities.