Even more mindblowing: said circle is mostly water.
This simple but eye-opening take on global population distribution comes from redditor valeriepieris, who writes:
Additional things I've realized: There are more Muslims in the circle than outside of it. There are more Hindus in the circle than outside of it. There are more Buddhists in the circle than outside of it... The circle pulls all of this off while being mostly water and including the most sparsely populated country on earth (Mongolia).
Yes, we realize this is a compromise projection (a Winkel Tripel projection, to be exact) and that the "circle" in this image is not actually a circle, but that's besides the point. What's truly noteworthy about this visualization is how clearly and effectively it conveys an astonishing truth about the world. More to the point: the design concept is so straightforward, a 5-year-old can wrap her head around its meaning; and yet the ideas and discussions it engenders – about population density, about government, about political ideologies, about the expansion of human populations – are effectively limitless. Several such discussions have popped up over on reddit. You can check them out here.

...also 99.9% of the world Panda population...
Hats off, valeriepieris. This one had us rubbing our eyes in astonishment.