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National Ice Core Laboratory. Section of ice from an ice core at the National Ice Core Laboratory, Denver, Colorado, USA, showing bubbles trapped inside the ancient ice. This lab stores 19,000 metres of ice cores from Antarctica, Greenland, and North America, and makes them available to scientists studying climate change and other issues. The lab is part of the U.S. Geological Survey (USGS), funded by the National Science Foundation. (KEYSTONE/SCIENCE PHOTO LIBRARY/JIM WEST/SCIENCE PHOTO LIBRARY)