Edinburgh Castle, located in Edinburgh Scotland is a historic fortress that dominates the skyline of the city. Perched on “Castle Rock”, the site has been occupied since the Iron Age (200 AD) or possibly late Bronze Age to present.
The first recorded castle was constructed in the reign of David I in the 12th century, and continued to be a Royal residence until 1633. By the 17th century, the castle became a military barracks and more recently in history, a popular tourist attraction and national monument for Scotland.
Unbeknown to the castle builders of the time, Castle Rock is the plug of an extinct volcano estimated to have formed around 350 million years ago during the carboniferous period.
The plug formed over a volcanic pipe which cut through the surrounding sedimentary rock, before cooling to form a hard material called dolerite. This strong robust material protected the plug from glacial movements and erosion which is why it survived over millions of years.