This SPOT satellite image of Tokyo Bay, Japan, has been coloured to reveal areas of different land use more clearly. The vast and sprawling urban areas of vegetation are orange, while water is black. Tokyo city is at the north of the west coast of the bay (top center) and Yokohama port is to its south (center). They were once separate cities but urban expansion has joined the two to form a huge, densely populated metropolis that is the largest city in the world, with the most expensive land prices.