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Union of the "Snakes"Captured in a microscope photograph submitted to National Geographic's My Shot photo community by U.K.-based Greg Parker, two strands of the snaking Spirogyra algae sexually reproduce. So-called conjugation tubes link the strands' cells, allowing them to exchange genetic information. Often seen floating in thin strands on freshwater streams and ponds, Spirogyra cells are filled with chloroplasts—packets of chlorophyll that allow the plants to generate energy via photosynthesis—whose spiraling shapes give the genus its name. (Related pictures: "Thick Green Algae Chokes Beach-Swimmers Dive In.") Why We Love It "Water bottles? Art? A view into the microscopic world that surrounds us is at once alien and familiar."—Sarah Polger, senior photo editor "These slimy algal cells are quite beautiful under the right lighting (and magnification)."—Chris Combs, news photo editor

Photograph by Greg Parker, My Shot