US President Barack Obama awards the National Medal of Science to Dr. Simon Levin, Princeton University, for international leadership in environmental science, straddling ecology and applied mathematics, to promote conservation; for his impact on a generation of environmental scientists; and for his critical contributions to ecology, environmental economics, epidemiology, applied mathematics, and evolution at the White House in Washington, DC, on May 19, 2016. / AFP PHOTO / Nicholas KammNICHOLAS KAMM/AFP/Getty Images
