Nancy LaMotte's eyes are a clear blue-green, the color of antique Coca-Cola bottles, but brighter. She scans the sand at her feet: gritty knots of seaweed, smashed oyster shells, driftwood – wait!

NPR goes on a coast-to-coast hunt for treasure hiding in plain sight. Learn about sea glass and how to find it. If you get out to the beach this summer, and say you've already caught up on all the ...