WRT and Archisystems International—as a joint venture called International Planning Associates (IPA)—fulfilled a two-year assignment for the Nigeria Federal Capital Development Authority to select the site and plan a new national capital city, Abuja, for an ultimate population of over 3 million. The city consists of a central area, which is home to the federal government, national institutions, and the central business district, and a series of residential mini-cities, each of which accommodates populations of 150,000 to 250,000 and is organized around local business and employment centers. The government approved the plan and began construction immediately. In 1991, Abjua became Nigeria's new capital, and today has a population of nearly 300,000.