United Kingdom (UK) is a North-Western European country. Its capital city, London is an important global city and financial center with an urban population of 10,310,000, the fourth-largest in Europe and second-largest in the European Union. UK has the world's fifth-largest economy by nominal GDP and ninth-largest economy by purchasing power parity.
The total area of the United Kingdom is approximately 243,610 square kilometres which includes the island of Great Britain, the northeastern one-sixth of the island of Ireland and some smaller surrounding islands. It lies between the North Atlantic Ocean and the North Sea with the south-east coast coming within 22 miles (35 km) of the coast of northern France, from which it is separated by the English Channel. In 1993 10% of the UK was forested, 46% used for pastures and 25% cultivated for agriculture.
The UK service sector makes up around 73% of GDP. Tourism is very important to the British economy and, with over 27 million tourists arriving in 2004, the United Kingdom is ranked as the sixth major tourist destination in the world and London which is a capital city, has the most international visitors of any city in the world. Between 2004 and 2008 the UK produced 7% of the world's scientific research papers and had an 8% share of scientific citations, the third and second highest in the world.
In Physics, Medicine and Chemistry, this island nation produced 118 Nobel laureates so far. Tomas Robert Lindahl is a Swedish-born British scientist specialising in cancer research who was awarded Nobel Prize in Chemistry in 2015 for mechanistic studies of DNA repair. John O'Keefe is an American-British neuroscientist who was awarded Nobel Prize in Physiology and Medicine in 2014. Numerous clinical journals are published from UK with good reputation. Scientific journals produced in the UK include Nature, the British Medical Journal and The Lancet.