Isfahan, historically also rendered in English as Ispahan, Spahan, Sepahan, Esfahan or Hispahan, is a major city in Iran, Greater Isfahan Region. It is located 406 kilometres south of Tehran and is the capital of Isfahan Province. Isfahan has a population of approximately 1.5 million, making it the third-largest city in Iran after Mashhad and Tehran, but was once one of the largest cities in the world.