The area is characterised by attractive small towns and villages built of "Cotswold stone" (a yellow limestone). This limestone is rich in fossils. In the Middle Ages, the wool trade made the Cotswolds prosperous. Some of this money was put into the building of churches so the area has a number of large, handsome Cotswold stone "wool churches". The area remains rich and has attracted rich people who own second homes in the area or have chosen to retire to the Cotswolds.