Canberra is a planned city and the inner-city area was originally designed by Walter Burley Griffin, a major 20th-century American architect. Within the central area of the city near Lake Burley Griffin, major roads follow a wheel-and-spoke pattern rather than a grid. Griffin's proposal had an abundance of geometric patterns, including concentric hexagonal and octagonal streets emanating from several radii. However, the outer areas of the city, built later, are not laid out geometrically.