It's difficult to get a handle on the population density around the world. Fortunately, this visualization makes it a little easier to get your head round.
Put together by Derek Watkins, it's actually interactive: you get to use a slider to shift the population density and see it change before your eyes. You should head to his website to try it out for yourself. The image above shows the areas around the world that home 5 people per square mile or more.
It gets more interesting as you crank the population density slider up, though. A ten-fold increase wipes out much of the land mass, sure, but the area of the world home to 50 people per square mile or more still provides an identifiable map.
Move to a hundred times the orignal figure however—at 500 people per square mile or more—and virtually everything disappears.