2-368-148 - Peter Thompson/Heritage Images

Dun Carloway, Isle of Lewis, Outer Hebrides, Scotland, 2009. Dun Carloway is an example of a broch, an ancient round, dry stone, hollow-walled building found in Scotland. Archaeologists are divided as to their purpose, with some believing they served a defensive purpose while others think they were farmhouses. The one at Carloway is particularly well preserved. It is thought to have been built in the 1st century BC and to have been occupied until around 1300. It is a large structure, measuring over 14 metres in diameter, 9 metres in height and with walls 3 metres thick.