Edinburgh Castle Rock is a black basalt rock, located in the old city of Edinburgh, often considered a hill. No one will deliberately use Castle Rock as a scenic spot, but in fact, Edinburgh Castle, the most famous scenic spot in Edinburgh, is situated on Castle Rock. Climbing this rock overlooks the whole city of Edinburgh.
About 300 million years ago, Castle Rock was an eruptive volcano that was buried beneath dunes and mud when volcanic activity stopped. In the Middle Ages, the builders chose a golden section here and saw evidence of the formation of volcanoes on the castle floor and outside.
On the back of the castle, it's almost 90 degrees vertical.