'Blue Moon' Seen Around the World

A full moon is seen behind tree branches in Skopje on August 31, 2012. According to NASA, this is the second time in August that a full moon is seen - the first was on August 1 to 2. This phenomenon, which is referred to as the 'blue moon', happens every two and a half years on average. (ROBERT ATANASOVSKI/AFP/GettyImages)