Edinburgh city lies on the east coast of Scotland, on the south bank of the Firth of Forth (the ‎estuary that opens into the North Sea). Geologically, the Firth of Forth is a fjord, carved by ‎the Forth glacier at the Last Glacial Maximum. The famous Edinburgh Castle is situated on ‎the top of a volcanic rock intrusion which was resistant to erosion by the ice sheet, and so ‎stands above the surrounding area; a perfect defensive site! ‎