The Roman agora was the centre of commercial activity of the city during Roman Times. It was constructed between 19 and 11 B.C. by the Roman Emperor Augustus to accommodate the commercial enterprises of the city, with shops, storerooms and offices. The Roman Agora consists of a large, open-air courtyard surrounded by colonnades on all four sides. The main interest of this Agora lies in the Tower of Winds, or the Horologion of Andronikos of Kyrrhos, is a tall, octagonal building immediately east of the Roman Agora. It was designed by a famous astronomer (Andronikos of Kyrrhos) to be an elaborate water clock (on the inside), sundial (on the outside), and weather vane (on the top). The nickname “Tower of the Winds” is derived from the personifications of the 8 winds carved on the 8 sides of the building.