Opposite the single-iwan old mosque in Eresk you can see a few mud-built buildings, but there's a whole lot more hidden in an Old Town section that lies just behind, layered higgledy-piggledy down a gentle ridge – above which rises a trio of rocky outcrops, each topped with a mud-brick watch-tower and curtain wall.
Eresk is 24km from Boshrooyeh, on the Deyhuk–Raqeh road, which parallels a mountain range rising abruptly from the flat plain.