This photo that's been going around purports to show all the little critters found in a single drop of seawater, magnified 25 times. It's a beautiful photo, but there's just one problem: it's not really a single drop of seawater (though it is probably magnified 25 times).
http://animals.io9.com/that-drop-of-seawater-photo-was-more-than-a-bit-misle-1578608896