visualizing density

After reading this article from Fortune (forwarded by Sol), I worked out a 3d chart using wikipedia data comparing the relative land areas and population densities of a few megacities.

The chart represents land area in square kilometers along the x,y axis (width and depth), and population density in people per square kilometer along the z axis (height).

The tall red column represents Metro Manila's density and area vs. other megacities. We're nearly three times the density of Hongkong occupying little more than half HK's land area. Even Mumbai distributes its density a little better.