Estimated to be in length, the levee was completed circa 1453. The levee kept fresh spring-fed water in the waters around and kept the brackish waters beyond the dike, to the east. Two double aqueducts, each more than long and made of terracotta, provided the city with fresh water from the springs at . This was intended mainly for cleaning and washing. For drinking, water from mountain springs was preferred. Most of the population liked to bathe twice a day; was said to take four baths a day. According to the context of Aztec culture in literature, the soap that they most likely used was the root of a plant called (Saponaria americana), and to clean their clothes they used the root of (Agave americana). Also, the upper classes and pregnant women washed themselves in a , similar to a sauna bath, which is still used in the south of Mexico. This was also popular in other Mesoamerican cultures. City plans The city was divided into four zones, or camps; each camp was divided into 20 districts (calpullis, , , meaning "large house"); and each calpulli, or 'big house', was crossed by streets or . There were three main streets that crossed the city, each leading to one of the three causeways to the mainland of , , and . Bernal Díaz del Castillo reported that they were wide enough for ten horses. Surrounding the raised causeways were artificial floating gardens with canal waterways and gardens of plants, shrubs, and trees. The calpullis were divided by channels used for transportation, with wood bridges that were removed at night. The earliest European images of the city were woodcuts published in Augsburg around 1522. Marketplaces Each calpulli had its own (marketplace), but there was also a main marketplace in – 's sister city. Cortés estimated it was twice the size of the city of Salamanca with about 60,000 people trading daily. Bernardino de Sahagún provides a more conservative population estimate of 20,000 on ordinary days and 40,000 on feast days. There were also specialized markets in the other central Mexican cities. Public buildings In the center of the city were the public buildings, temples, and palaces. Inside a walled square, to a side, was the ceremonial center. There were about 45 public buildings, including: the Templo Mayor, which was dedicated to the Aztec patron deity and the Rain God ; the temple