Falak-ol-Aflak Castle is one of the most impressive castles of Iran. It is situated on the top of a large hill inside the city of Khorramabad  the center of the Luristan province. This gigantic structure was built during the Sassanid era (226–651AD).

Archeologists found out that the Sassanid engineers had equipped Falak ol-Aflak Castle with a dehumidifier system which is one of the wonders of the ancient world.

The castle used to have 12 towers. It is 2,860 meters in perimeter and its tallest wall is 22.5 meters high. Iranians are exploring the ways to introduce the Falak-ol-Aflak to the UNESCO for the World Heritage List.

See Lorestan province cultural heritage organization.