Size of humankind

How large is humankind in volume? Surely we're many, so our volume must be huge, isn't it?

It seems from Wolfram Alpha that the average human volume is around 66.4 liters. The current human population is 6.93 billion people.

Therefore all humankind is 4.602 * 10^11 liters of stuff, which correspond to a cube with a side of 772 meters or a sphere with slightly less than 1 km diameter.

This roughly corresponds to couple of hills or a small lake. There is plenty of icebergs larger than that. We would be barely a blip on a map of the planet: Lake Garda in Italy is more than 100 times larger. Wolfram Alpha tells us that it's 0.92 times the water in the Sydney Harbour, but it hardly seems suggestive to me, perhaps because I'm not Australian.