Bill Gates recently called out a staggering fact from the historian Vaclav Smil:

This might be the most mind-blowing fact I learned this year: http://t.co/jJB3cEoq7j pic.twitter.com/Dr34RLeJbU — Bill Gates (@BillGates) December 12, 2014

The significance of cement can't be understated. A powdery substance made with calcined lime and clay, it is a binder that enables the creation of concrete (along with water and gravel or sand).

Concrete, according to Smil (whom Gates calls his favorite author), is the most important man-made material in history. It has been used in everything from the Pantheon to the Hoover Dam to China's incredibly big Three Gorges Dam.

Where there's cement consumption, there's growth, and there's never been anything like what's happening in China.