Tehran or Teheran (; Persian: تهران Tehrân ) is the capital of Iran and Tehran Province. With a population of around 8.7 million in the city and 15 million in the larger metropolitan area of Greater Tehran, Tehran is the most populous city in Iran and Western Asia, and has the second-largest metropolitan area in the Middle East (after Cairo). It is ranked 24th in the world by the population of its metropolitan area.