A visible part of Himachal's map is coloured blue and well over one percent of its mass is under some form of water - lakes and rivers and glaciers. Of the lakes, some are natural bequests that date back millions of years to the time when the region was a vast inland sea and today, they are fed by streams of pure snow-melt or by groundwater springs. Practically without exception, they are held sacred - or at the very least, have fascinating legends lapping their crystal-clear waters. Other lakes are far more recent and are man-made reservoirs. Many are sources of the rivers that start as tiny streams and grow to become the giants that feed the fertile valleys of the State and the Gangetic plains of north India. Several are home to a variety of resident and migratory birds, and a host of aquatic life. These water-bodies have also opened a tremendous range of activity and adventure that includes boating, swimming, canoeing, water-skiing, kayaking, sailing, surfing and fishing.