this tiny sphere represents all the world's water.
The sphere is about 1400km in diameter, including oceans, groundwater and water vapour.
That may seem like a lot, but very little of it is freshwater, only about 4%, and most of that is locked up in glaciers and polar ice caps.
The earth may look like a blue marble from space, but in actuality there's precious little blue on it. And we better take care of it.