Twisted Sifter has a great gallery of snowflake and ice crystal electron microscope photos. At this level of magnification, the ice looks like metal that has been machined by space aliens.
Mark Frauenfelder is the founder of Boing Boing and the editor-in-chief of MAKE and Cool Tools. Twitter: @frauenfelder. Come and hear Mark speak at the ALA conference in Chicago on July 1.