Sometime between 579 and 323 BC during the Achaemenid Persian period, the Citadel of Bam (in Persian Arg-é Bam) was built in southeastern present-day Iran, a huge fortress made of clay that is considered to be the largest adobe building.

It is located next to the city of the same name in the province of Kerman and near the border with Pakistan, and consists of a large fort that contains an inner citadel (although today the entire complex is called a citadel).

Photo: Tatsiana Hendzel | Dreamstime.com