Svalbard is an archipelago in the Arctic that constitutes the northernmost part of Norway. It is located about 650 km north of mainland Europe, midway between mainland Norway and the North Pole. The group of islands are inside the Arctic Circle. Spitsbergen is the largest island and has the administrative centre of Longyearbyen. The islands were first used as a whaling base in the 17th and 18th centuries. Several species of whales were hunted to near-extinction and whaling eventually ceased. Coal mining began in the early 1900s, and several permanent communities were established. Research and tourism have become important supplementary industries. No roads connect the settlements; instead snowmobiles, aircraft and boats serve inter-community transport. The flora and fauna take advantage of the long period of midnight sun. Svalbard is a breeding ground for many seabirds, and also features polar bears, reindeer and marine mammals. Seven national parks and twenty-three nature reserves cover two-thirds of the archipelago, protecting the largely untouched, yet fragile, environment. Sixty percent of the archipelago is glacier, and the islands feature many mountains and fjords.