The National Research Council divides Thailand into six geographical regions, based on natural features including landforms and drainage, as well as human cultural patterns. They are, namely: the North Region, the Northeast Region, the Central Region, the East Region, the West Region and the South Region of Thailand. Although Bangkok geographically is part of the central plain, as the capital and largest city this metropolitan area may be considered in other respects a separate region. Each of the six geographical regions differs from the others in population, basic resources, natural features, and level of social and economic development. The diversity of the regions is in fact the most pronounced attribute of Thailand's physical setting.