The island lies roughly equidistant between England, Ireland, Scotland, and Wales. The Isle of Man is not part of the United Kingdom but is rather a crown possession (since 1828) that is self-governing. The Isle of Man is about 48 km long by 16 km wide. Man’s coastline is rocky and has fine cliff scenery. The grass-covered slate peaks of the central massif are smooth and rounded due to action during various glacial periods. To the southwest lies an islet, the Calf of Man, with precipitous cliffs, which the Manx National Heritage administers as a bird sanctuary.