Sand. Civilizations modern and ancient have been held up by the stuff. It's one of the main building components in construction.
When you look at those mega-cities in sprouting up in China, one could say you're looking at giant sandcastles.
But sand is finite. And people are starting to kill for it.
Vince Beiser explores this for Wired magazine in "The Deadly Global War for Sand." Before you dive into the incredible read, here are seven things Beiser says you should know about sand: