A thousand-person crew swept the streets of this city daily, and would collect biodegradable trash to be incinerated for lighting. This city's thorough waste management system used canoes to collect human urine to use as a mordant in fabric dying as well as excrement for fertilizer, creating zero toxic waste. The residents of this city built a 10-mile long dike to separate a neighboring saltwater lake from its (*) namesake freshwater lake. This city was supplied with water by a dual-pipe aqueduct made of clay that was rebuilt in stone after it was washed away by a flood. Lake Xochimilco still contains examples of the structures this city was built upon in neighboring Lake Texcoco. (10[1])For 10 points, name this city built on artificial islands called chinampas, the capital of the Aztec empire. ■END■