Popsci Images 2007 09 Smallworld 8 Hunnekuhl 1048
Pop Sci has an amazing gallery from Nikon’s annual Small World Competition, some of the photos are of subjects less than half a millimeter! Link.

Pictured here, Erpobdella octoculata (fresh water leech), magnified 25x. Photograph by Vera Hunnekuhl