Keshan is a city of about 300.000 people, situated in the Isfahan province in central Iran. It is rather low lying, and it gets very hot in summer. Traditionally, people have sought to alleviate this by building the houses into the ground. Keshan produces both wool and silk rugs. The first have a cotton warp and weft, the weft being blue. Several qualities are produced, but most Keshan rugs are very finely knotted and all covering. The shape of a Keshan medallion is quite special; it is made by alternating curved lines and right angles. The most common colours are a red field and a blue medallion, with secondary details in other colours. The trimmings of a Keshan rug are also special; the main trimming is normally surrounded by stripes that form a geometrical pattern, usually small blue and red triangles. Keshan rugs come in all sizes. The south-eastern city of Natanez has laid name to image rugs done in the same knotting as Keshans.