Sand is essential for modern construction. Almost every new office tower, road and shopping mall being built in Asia’s booming cities is made with concrete mixed with sand. And to get more sand, companies and people are pulling sand out of rivers and oceans at an unprecedented rate, say scientists. And in the deep ocean waters off the U.S., sand is being excavated to restore coastlines from Louisiana to New Jersey. Some estimate that extracting sand is a $70-billion industry. Diane and a panel of guests take a look at the increasing demand for sand, and concerns about the impact of dredging on river and ocean life worldwide.