On the promontory of Kinnaird Head, on the north-east coast of Scotland, sits a peculiarly designed lighthouse. It is an exception in history - the only lighthouse in the world to be built into a castle. Originally constructed in 1571 by Sir Alexander Fraser, the castle towered over his new town of Fraserburgh with Scotland's forgotten university built in its shadow. For 200 years this small tower played host to lairds, lords and Jacobites before abandonment in 1750. The castle was saved from ruin in 1787 when the newly formed Northern Lighthouse Board transformed it into their first Scottish lighthouse. Every Stevenson engineer visited and left their mark on the site, while a never-ending watch of keepers kept the light flashing for 200 years. With automation in 1991 there was a second abandonment of the old tower, until it made its latest transition from lighthouse to museum. Since 1995 it has been Scotland's most visited lighthouse, frozen in time as a monument to the manned lighthouses of old.