Early Mauryan Pataliputra was mostly built with wooden structures. The wooden buildings and palaces rose to several stories and were surrounded by parks and ponds. Another distinctive feature of the city was the drainage system. Water course from every street drained into a moat which functioned both as defence as well as sewage disposal. According to Megasthenes, Pataliputra of the period of Chandragupta, was "surrounded by a wooden wall pierced by 64 gates and 570 towers— (and) surpassed the splendors of contemporaneous Persian sites such as Susa and Ecbatana".