As part of NASA's IceBridge mission, an airborne survey revealed a group of mysterious ice holes in the Arctic ocean, some 50 miles northwest of Canada's Mackenzie River Delta. Mission scientist John Sonntag said the holes were something he'd never seen before. One theory is that the holes might have a mammalian origin, gnawed out by seals as a place to breathe after surfacing up from the icy waters. More on the mystery at Newsweek.