Cottonwood trees in the American West are a nuisance to some and a treasure to others. They yield shade, beautiful foliage and, in June, a kind of warm, fluffy "snow."
More tornadoes occur in the U.S. than any other country, mainly in the Great Plains, Midwest and southern states. Two meteorology professors answer questions.
Happening now in Denmark: "bright nights," when the sun is never far below the horizon. Photographer and videographer Adrien Mauduit tells the story and provides stunning imagery.