Namibia's 'fairy circles': Nature's greatest mystery?

Story highlightsStrange barren dots -- rimmed with tall grasses -- sprinkle a 1,100-mile stretch of Namibia's desertThese are known as fairy circles, and their cause remains a mysteryLast year, a theory that termites caused the circles made international headlinesA German scientist thinks competition for resources is the causeFrom the air, the Namibian desert looks like it has a bad case of chicken pox. Spread across 1,100 miles of a narrow strip sit a smattering of barren polka dots, otherwise known as fairy circles. These sizable craters measure 10- to 65-feet in diameter, and represent one of nature's greatest mysteries.

Over the decades, a number of theories, from alien invasion