In the year 2020 we passed an alarming milestone. Earth is now covered in more man made mass than naturel biomass. Much of this material is built using sand, and researchers say  we are facing a looming global sand crisis as a result. 

Adding to the problem is that all sand is not made the same. The sand found in abundance in desert around the world is actually unsuitable for use in construction aggregates because desert sand grains are too round to stick together well to make good concrete. The best sand is found underwater, like at the bottoms of lakes and rivers, as well as on beaches and riverbank.