The island lies roughly equidistant between England, Ireland, Scotland, and Wales. The Isle of Man is not part of the United Kingdom but rather is 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 as a result of action during various glacial periods. To the southwest lies an islet, the Calf of Man, with precipitous cliffs, which is administered by the Manx National Heritage as a bird sanctuary.