At the centre of the main urban area (approximately the first from Tokyo Station) are the 23 special wards, formerly treated as a single city but now governed as separate municipalities, and containing many major commercial centres such as Shinjuku, Shibuya, Ikebukuro and Ginza. Around the 23 special wards are a multitude of suburban cities which merge seamlessly into each other to form a continuous built up area, circumnavigated by the heavily travelled Route 16 which forms a (broken) loop about from central Tokyo. Situated along the loop are the major cities of Yokohama (to the south of Tokyo), Hachiōji (to the west), Ōmiya (now part of Saitama City, to the north), and Chiba (to the east). Within the Route 16 loop, the coastline of Tokyo Bay is heavily industrialised, with the Keihin Industrial Area stretching from Tokyo down to Yokohama, and the Keiyō Industrial Zone from Tokyo eastwards to Chiba. Along the periphery of the main urban area are numerous new suburban housing developments such as the Tama New Town. The landscape is relatively flat compared to most of Japan, most of it comprising low hills.