Pictured here are Eastern Island and Spit Island, the two smallest of the three islands in the Midway Atoll, located about 3,200 miles west of San Francisco and 2,500 miles east of Tokyo. The atoll was formed as a shield volcano roughly 28 million years ago. Over the millennia, the volcanic island subsided under the sea but the coral reef encircling it has maintained itself and protected the atoll"s three, low-lying islands (Sand Island, not shown in our photo, is the third).