Ailsa Craig Scottish Gaelic: Creag Ealasaid) is an island of 99 hectares (240 acres) in the outer Firth of Clyde, 16 kilometres (10 miles) west of mainland Scotland, upon which blue hone granite was quarried to make curling stones. The now uninhabited island is formed from the volcanic plug of an extinct volcano. The island, colloquially known as “Paddy’s milestone”, was a haven for Catholics during the Scottish Reformation in the 16th century, but is today a bird sanctuary, providing a home for huge numbers of gannets and an increasing number of puffins. Scotland (/ˈskɒt.lənd/; Scots: [ˈskɔt.lənd]; Scottish Gaelic: Alba [ˈal̪ˠapə] ( listen)) is a country that is part of the United Kingdom and covers the northern third of the island of Great Britain. It shares a border with England to the south, and is otherwise surrounded by the Atlantic Ocean, with the North Sea to the east and the North Channel and Irish Sea to the south-west. In addition to the mainland, the country is made up of more than 790 islands, including the Northern Isles and the Hebrides.