After the Opium War with the British, Shanghai was developed as a port of international trade. The small original Chinese settlement west of the Huangpu River was augmented by portions allotted to different foreign powers: the British and Americans in the International Settlement, the Russian Regiment, the French Concession, each with their own distinctive traditions. The form of these settlements reflects a western idea of urban form in contrast to the much more organic form of the Chinese core. Current modern expansion in Pudong on the East side of the river has developed at an unprecedented rate, every new building rushing to be taller than its neighbor.