Sometimes the ice melts in such a way that a cave is formed in the ice. As the sun shines on the thin walls around the cave the colors on the ice are very beautiful. The ice looks green, purple, and blue instead of white like the rest of the glacier. Some bits of the ice hang down, or stick up, like great icicles. The icicles too are bright colors in the sunshine. Sometimes visitors to the glacier go into the cave or walk about on the ice. They do not stay long, for the ice cracks and pops and makes a great deal of noise. The visitors are always told that pieces of ice often break off the glacier and come sliding down. Fredrik has been up to the top where the great ice-sheet lies for miles, and miles, and miles. You may be sure that Fredrik was not alone on the glacier. He went with a guide who knew where all the cracks in the ice are. Walking on a glacier is dangerous for a person who does not know the ice. The ice is most dangerous when soft snow covers the deep cracks in the ice. Then a traveler may step on some soft snow and drop several feet into the ice. But travelers say that a walk on a glacier is great sport for people who have learned how to walk there. Many travelers from different parts of the world go to Norway to climb glaciers. Freezing and thawing made the rocks on the mountain crack and break. So after the glaciers passed, the low places between the mountains were cut deeper. Water from the sea came in to fill those low places and make the fjords. [Illustration: A NORWEGIAN FJORD] So the great ice sheets were the _real_ giants that made the sharp peaks of the mountains, the waterways, and the lakes of the north land. Of course, much of the snow which falls on the mountains does melt and run off in streams. Sometimes the rivers flow rapidly down steep slopes. Sometimes the water tumbles over a high rocky bank and falls hundreds of feet to land below. The people of the north lands have put some of the falls to work. For years the falling water has turned wheels that have run mills to grind grain and to saw logs. But now the water of some of the great falls has been turned into electricity. High in the mountains are large houses where the water is made into the new power. From the power-houses electricity is sent for miles and miles to light homes and to run machines in factories. Norway has no coal. The Norwegians turn the water into heat and power such as coal makes. Sometimes people in Norway call the waterfalls their “white coal.” So waterfalls are also mountain giants. People who visit Norway and its mountains are almost sure to come away believing in giants—but not _fairy-tale giants_. In the Land of Evergreen Trees