The Renaissance Center in Detroit, Michigan, as viewed from across the Detroit River. Designed by John Portman and completed in 1977, this complex initially consisted of a five-tower rosette rising from a common base; two further towers were added in 1981. The central tower, measuring 73 floors in height, is the tallest building in Michigan. Since 1996, the complex has been owned by General Motors and used as its world headquarters; the complex also houses a shopping center, hotel, restaurants, brokerage firms, and banks.Photograph: Chris Woodrich