Tehran, sometimes spelt Teheran, is the capital of Iran and Tehran Province. With a population of 8,429,807 it is also Iran's largest urban area and city, one of the largest cities in Western Asia, and is the 21st largest city in the world. Tehran is the centre of most Iranian industries including automotive, electrical, military, weaponry, textiles, sugar, cement, and chemical. It is also a leading centre for the sale of carpets and furniture. There is an oil refinery located south of the city. In the 20th century, Tehran was subject to mass-migration of people from all around Iran. The main and original inhabitants of the city are Persians and the principal language of the city is Persian with Tehranese accent spoken natively by over 98% of the city's population.