This is a fascinating read!

Although Singapore is itself an island nation, it ran out of its own sand many decades ago. Today the entire island consists of urban areas or protected-environment sanctuaries. This shortage has fueled a massive industry, worth at least $1 billion between 1998 and 2008. And it’s only growing: In 2008 alone, according to its own figures, Singapore imported more than $273 million worth of sand, more than any other country in the world. But these numbers — which account for only the legal trade in sand — are only the tip of the iceberg.