In Glacier National Park (USA), there are more than 700 lakes with crystal clear water. Low water temperatures prevent the growth of plankton, but in Glacier Park is not unusual to see details at the bottom of a deep lake and up to 10 meters. One of the most striking characteristics of some of these lakes is the presence of colorful pebbles under water and on the banks. One of the most famous lakes with “colored stones” Lake McDonald is located on the west side of the park. It is also the largest, longest and deepest lake in Glacier National Park.