Norway comprises the western part of Scandinavia in Northern Europe. The rugged coastline, broken by huge fjords and thousands of islands, stretches 25,000 km and 83,000 km. Much of the country is dominated by mountainous or high terrain, with a great variety of natural features caused by prehistoric glaciers and varied topography. The most noticeable of these are the fjords: deep grooves cut into the land flooded by the sea following the end of the Ice Age. Because of the large latitudinal range of the country and the varied topography and climate, Norway has a larger number of different habitats than almost any other European country. There are approximately 60,000 species in Norway and adjacent waters (excluding bacteria and virus). The Norwegian Shelf large marine ecosystem is considered highly productive. The country is richly endowed with natural resources including petroleum, hydropower, fish, forests, and minerals. Large reserves of petroleum and natural gas were discovered in the 1960s, which led to a boom in the economy. Norway has obtained one of the highest standards of living in the world in part by having a large amount of natural resources compared to the size of the population. In 2011, 28% of state revenues were generated from the petroleum industry. Norway is the first country which banned cutting of trees (deforestation), in order to prevent rain forests from vanishing. The country declared its intention at the UN Climate Summit in 2014.