Khorramabad is a city and capital of Lorestan Province, Iran. Khorramabad is situated in the Zagros Mountains. The city population is predominantly Lur and Lak, although the two groups are closely related. In the city center, a tall citadel called Falak-ol-Aflak (The Heaven of Heavens), a relic of the Sassanid era, is now a nationally popular museum.