This brick fortress in the centre of town was built in the 1760s by Karim Khan Zand, the founder of the short-lived Zand dynasty that briefly made Shiraz the capital of Iran. The Arg is rectangular, with massive round towers at each corner — one of which leans noticeably, the result of subsidence under the old bathhouse foundations beneath it.
Inside, the rooms have been restored as a small museum showing how the Zand court lived: an orange-tree courtyard, a private hammam, and reception halls with painted ceilings. The Arg later served as a prison under the Pahlavis, and a few of the cells are preserved. Combine a visit with the Vakil complex next door — they are all within five minutes' walk.