When you are travelling along the Sognefjord, and especially by boat, and feel you have had your fill of vertical mountainsides and cascading waterfalls for a day, you are advised to turn your attention to the small high farms clinging on for dear life. For many of these farms - and some are still inhabited - the fjord is in many cases the only way to travel. You may also observe on your way in or out the Sognefjord that the weather may change quite dramatically. At the mouth of the fjord the climate is maritime, whereas the innermost parts of the 200-km-long fjord have a much drier inland climate. It is a well-established fact that it is not easy to sail on the Sognefjord. The currents may be strong in some places, and they may quickly change directions. In some places winds may blow hard whereas the very same wind direction may give calm waters around the next point of land. Some days you may see differently coloured current patterns on the fjord surface, and these are extensions of the river flows. These fluvial currents guide the wild salmon back to their river of birth to spawn. Occasionally you may still observe the wooden structures formerly used by local farmers as observation posts to catch the wild salmon in nets. This fishery used to be an important export industry, and in the wintertime ice was cut in the lakes and stored in special houses to be used in summertime to keep the salmon as fresh as possible. Nowadays the wild salmon is an endangered species, but when you visit Laerdal and the Norwegian Wild Salmon Centre, you may learn more about the salmon and traditional fishing methods. If you are very lucky, you may even get a chance to see the "live" spawning rituals of the wild salmon. At the Sognefjord Aquarium in Balestrand you may experience the interesting diversity of marine life in the fjord.