houses ceramics and carvings from the area of Cerro de la Madera, in Zihuatanejo, among others. Room three features the Tierras Prietas site, the cultivation of food plants and use of natural resources such as the bajareque technique of walls made of interwoven branches and clay. Room 4 covers aspects of village life and cultural exchange from 200 to 750 A.C.; the introduction of ball games and new pottery techniques. Room five contains pieces from the Aztec period from 1487 to the 1520s, when the province of Cihuatlan was established, and tribute was paid to the Aztecs by the local population in shells, chocolate, basketry and textiles. Room six covers the colonial period and search for a maritime route to the west during the 16th and 17th centuries. During this time the ports of Zihuatanejo and Acapulco were important points of reference for Spanish and other navigators. The bay and its beaches The town of Zihuatanejo's main attraction is its bay, which is well-protected from open ocean. It is a favorite place to moor boats from small private ones to large yachts during the winter months. The bay's width varies from between in width and averages deep. It is mostly surrounded by beaches, most of which have gentle waves. On land the bay is surrounded by the foothills of the Sierra Madre mountains. Development of this area has caused some environmental problems. The town's five water treatment plants can no longer keep up with demand, with some untreated wastewater and sediment flowing into the bay. There has also been some wholesale destruction of the hills right on the bay to create development space, and there is concern about damage to the local coral reef. Some development projects, such as a dock for cruise ships and Punta del Mar (a complex of hotels, villas, pools and a marina) have been delayed due to the need for environmental impact studies. The ring of beaches of Zihuatanejo Bay begins with the Municipal Beach which is in front of the town center and next to the port. From there, there is a cement and sand walkway that leads to Playa Madera (Wood Beach). It is a stretch of light-colored sand between the municipal beach and Playa La Ropa. The waves here are gentle with the occasional wave. This beach contains a number of bay-view restaurants, bungalows, condominiums and hotels, as well as a walkway