Great Britain is situated on the British Isles. It consists of England, Wales, Scotland and Northern Ireland, and is one thirtieth the size of Europe. Great Britain is surrounded by seas on all sides and is separated from the continent by the North Sea and the English Channel. There are many rivers in Britain. They are not long but some of them are deep. The longest river is the Severn. There are many mountains in the north of England and in Scotland but they are not very high. The highest mountain in Great Britain is Ben Nevis. There are many lakes in Scotland. The most beautiful is Loch Lomond. Great Britain has a very good position as it lies on the crossways of the sea routes from Europe to the other parts of the world. There are many countries which are connected with Great Britain by sea. Thanks to Gulf Stream the climate of Great Britain is mild. It is often foggy and rainy. The summer is not very hot and the winter is not very cold. Great Britain is a highly developed industrial country. It lives by manufacture and trade. Its agriculture provides only half the food it needs, the other half of its food has to be imported. Britain is one of the most highly industrialised countries in the world: for every person employed in agriculture, eleven are employed in mining, manufacturing and building. The main branches of British economy are engineering, mining, ship-building, motor vehicle manufacturing, textile, chemistry, electronics, fishing and food processing. The industrial centres of Great Britain are London, Manchester, Eirmingham, Leeds, Liverpool, Sheffield and others.