The irregular coastline of Luzon provides several fine bays, most notably Manila Bay, which is considered the best natural harbor in E Asia and one of the finest in the world. N Luzon, which is drained by the Cagayan River, is very mountainous; the highest peak, Mt. Pulog, rises to 9,606 ft (2,928 m). In the east the great Sierra Madre range so closely parallels the shore that almost no coastal plain exists. Mountains extend generally along the entire length of the island, into the irregular Bicol peninsula to the southeast, where Mt. Mayon is the most famous volcano. In the west, the Zambales range runs from Lingayen Gulf S to Bataan peninsula. The island has two large lakes, Laguna de Bay and Taal. The inhabitants are almost all Christian and are principally Tagalogs and Ilocanos. Indigenous peoples include the Negritos and Igorots (the latter's famous rice terraces on steep mountain slopes are considered one of the agricultural wonders of the world).