Near the Danish city of Ikast, some 1,500 spectators gathered on Apr. 19 to celebrate what has become something of a national holiday at organic dairy farms around Denmark. Courtesy of Organic Denmark hide caption

itoggle caption Courtesy of Organic Denmark

Purdue University students are testing new software that may track and warn about tornadoes, such as this one which struck Rochelle, Ill., in early April. Walker Ashley/AP hide caption

itoggle caption Walker Ashley/AP

Mother and infant Bouvier's red colobus monkeys in a first-ever photograph of the primate taken in the Democratic Republic of Congo. The species was thought to have gone extinct in the 1970s. Lieven Devreese and Gaël Elie Gnondo Gobolo/Ntokou-Pikounda National Park, DRC hide caption

itoggle caption Lieven Devreese and Gaël Elie Gnondo Gobolo/Ntokou-Pikounda National Park, DRC

The mountain lion known as P-22 is seen in a photo from November after recovering from mange. He has been living in Griffith Park since at least February 2012. Courtesy of the National Park Service hide caption

itoggle caption Courtesy of the National Park Service

Food companies can make safety evaluations of their products in secret without ever telling the Food and Drug Administration. Luciano Lozano/Ikon Images/Corbis hide caption

itoggle caption Luciano Lozano/Ikon Images/Corbis