Ancient Arg-e Bam.
Most have never heard of it or have seen it.
The Arg-e Bam (Persian: ارگ بم), located in the city of Bam, Kerman Province of southeastern Iran, is the largest adobe building in the world. The entire building was a large fortress containing the citadel, but because the citadel dominates the ruins, the entire fortress is now named Bam Citadel.
