Being on the border of England and Scotland, Northumberland is noted for its undeveloped landscape of high moorland, now largely protected as a National Park. This features the World Heritage site of Hadrian's Wall stretching coast to coast. As a contrst to this the coastline (An area of Outstanding Natural Beauty) has a splendour of its own, dominated by huge skies. Northumberland is the most sparsely populated county in England and has the historic interest of a border county including a multitude of castle and fortified houses. The area to which Christianity first came to England adds further interest in the form of The Holy Island of Lindisfarne.