The urban area of London is shown as blue and green at the top of this infrared SPOT-1 image. London grew up along the River Thames, expanding rapidly during the nineteenth and early twentieth centuries, to be halted by the imposition of the Green Belt in 1938. Ironically, this helped to make the surrounding counties less rural in character as their towns became dormitories for workers commuting to London. This image shows some of the enlarged commuter towns (also blue and green) that vie for space among the fields (red) and the woodland (brown).