The seventh book in the Earthworks series offers a fascinating introduction to icy caps that have changed the face of our planet. Glaciers are powerful forces of nature--tremendous sheets of ice that can weigh millions of tons, crush boulders, and flatten forests. Some slide down to meet the sea, break off, and form icebergs. Greenland, home to the largest glacier on earth, forms more than 40,000 icebergs each year, including the infamous one that sunk the Titanic. A lively look at one of the earth's remarkable phenomena.