Central Honshu includes the Tokyo region (Kanto). It is the heart of Japan terms of population concentration and economic activity: 31 percent of the population produces 37 percent of Japanese GDP on less than 10 percent of the land. Tokyo, Kawaski and Yokohama fuse into a huge urban complex around Tokyo Bay. Tokyo itself, having 35 million people in 2003, is the world's most populous metropolitan area. Tokyo is Japan's center of government, finance, and internal and international service industries; Yokohama is Japan's busiest port; and Kawasaki has heavy industries. Oil refineries, steel mills, chemical plants, and power stations line the waterfront and cover large sectors of reclaimed land. The rest of the plain around this megacity still produces much rice, together with fruit, vegetables, poultry, and pigs for the nearby markets. Volcanic mountains around the northern and western margins of the bay area have winter sports facilities, and their hot springs attract other tourists.