http://www.oddee.com/item_96654.aspx
http://listverse.com/2012/02/08/top-10-spectacular-natural-phenomena/
http://www.technocrazed.com/worlds-top-10-most-incredible-natural-phenomena-photo-gallery
http://matadornetwork.com/trips/photo-essay-15-unusual-natural-phenomena-and-where-to-witness-them/
http://www.toptenz.net/top-ten-strangest-natural-phenomena.php
http://www.oddee.com/item_91568.aspx