in various other places. These persons incorporated nets, hooks, farming, ceramics and weaving to their everyday objects. The inhabitants of the coast lived in the lomas and the valleys, where they built temples and dwelling complexes, leading to huge ceremonial centres, such as the Huacoy on the Chillón River; Garagay and La Florida on the Rímac River, Manchay on the Lurín River; and Chancay, Supe and many other valleys to the north and south. There are finely ornamented temples with figures modelled in clay. Lithic prehistoric projectile points of Paijan type were found at Ancón, 40 kilometres northeast of Lima in the Chillón River Valley. The 5,000-year-old ruins known as El Paraíso are also located in this area. A temple at the site is believed to be about 5,000 years old. In 2006, a team of archeological researchers led by Robert Benfer announced their findings from a four-year excavation at Buena Vista in the Chillón River valley a few kilometres north of present-day Lima. They had discovered a 4200-year-old observatory constructed by an early Andean civilization, a three-dimensional sculpture, unique for the time period in this region, and sophisticated carvings. The observatory is on top of a 10-meter pyramidal mound and has architectural features for sighting the astronomical solstices. The discovery pushes back the time for the development of complex civilisation in the area and has altered scholars' understanding of Preceramic period cultures in Peru. The Lima culture (100 A.D. to 650 A.D.) arose in this area, specially in the central valleys from Chancay to Lurín. It was distinguished by painted adobe buildings. During this time, the Huari conquest took place, thus giving rise to Huari-style ceramics, together with a local style known as Nievería. As the population grew, their culture changed. With the decline of the Huari, whose most important center was Cajamarquilla, new local cultures arose. The Chancay are the most well-known. They developed large urban centers and a considerable textile production, as well as mass-produced ceramics. At this stage in the mid-15th century, the Incas arrived from their base in the Andes. They conquered and absorbed the regional cultures and occupied important sites such as Pachacamac, turning it into an administrative centre. Political divisions The department is divided into nine provinces, which are composed of 171 districts. Barranca (Barranca) Cajatambo (Cajatambo) Cañete (San Vicente de Cañete) Canta (Canta) Huaral (Huaral) Huarochirí (Matucana) Huaura (Huacho) Oyón (Oyón) Yauyos