This video of a UFO supposedly racing past the Popocatepetl Volcano near Mexico City has been viralizing around the internet lately. It purports to show a UFO racing toward the ominously smoking Popo crater, then flying into it. What it actually shows is a slightly sped up image of an observation plane circling the crater, then moving downward behind it. Such flights around Popo are common.

http://www.youtube.com/watch?v=b7n4uVIuamk
Story Source:
http://www.youtube.com/watch?v=b7n4uVIuamk