Researchers at the U.S. Geological Survey National Wildlife Health Center in Madison, Wis., use eggs to see if the Asian strain of the H5N1 bird flu virus has entered the U.S. in this photo from 2006. Andy Manis/AP hide caption

itoggle caption Andy Manis/AP

This satellite image from Oct. 28 shows Hurricane Sandy in the Atlantic Ocean before making landfall. NASA via Getty Images hide caption

itoggle caption NASA via Getty Images

The bubbles in champagne tickle the tongue and transfer wonderful aromas to the nose. iStockphoto.com hide caption

itoggle caption iStockphoto.com

Mosquitoes like this one can carry the virus that causes dengue fever, which may become a bigger problem in some regions as biodiversity is lost. James Gathany/CDC Public Health Image Library hide caption

itoggle caption James Gathany/CDC Public Health Image Library

Photographer Freya Najade journeys into the weird sci-fi world of Europe's agricultural production. In one cow-milking facility she visited, "two people are needed to milk twice a day 300 cows," she writes. Freya Najade hide caption

itoggle caption Freya Najade

Thousands of years ago, a mutation in the human genome allowed many adults to digest lactose and drink milk. iStockphoto.com hide caption

itoggle caption iStockphoto.com

People in Takoma Park, Md., walk toward a fallen telephone pole on June 30 after heavy overnight thunderstorms devastated the Washington, D.C., metropolitan area. The line of storms known as a derecho left over 1 million people without power. Kevin Dietsch/UPI/Landov hide caption

itoggle caption Kevin Dietsch/UPI/Landov