Two-and-a-half billion years ago, the earth was a very different place, but it already had life. Not anything you’d recognize, or could even see, but life of a sort anyway. While those archaic single-cell life form...

The Grand Prismatic Spring at Yellowstone National Park is so colorful that it’s hard to believe there aren't dyes or Photoshop involved. But the formation is totally natural. The hot spring is one of many geysers...