1 of 9
Pandora's box (virus)
Credit: Image courtesy of Chantal Abergel / Jean-Michel Claverie
Giant viruses, more than twice as big as the last largest known viruses, have now been unearthed from sludge across the world, researchers say.
Even more titanic viruses might await discovery, the scientists said, and they may have features that could blur the lines between life and viruses, which are not considered to be living things.
[Full Story: Largest Viruses Ever Revealed]