When we were kids, our family moved to Norfolk, Virginia, and beginning in 1956 we frequently visited Virginia Beach, building sandcastles and chasing sand fleas in the surf. From time to time we would find tar balls on the beach -- not many, and usually they turned up following a storm. The tar balls of Virginia Beach were relics of the early years of World War II. In 1942, a largely-hidden marine war took place off the shores of the Carolinas and Virginia as German U-boats lay in wait for unprotected merchant shipping northbound from the Gulf of Mexico.