The Half-Moon Battery at Edinburgh Castle, Scotland. The battery was constructed between 1573-1578 on top of the ruins of David's Tower (the residence of King David II), which was destroyed during the Lang Seige of 1571-1573. The battery was built to act as the castle's main high level defence on its vulnerable east side.

Until 1716 the battery was armed with seven bronze guns cast for James IV, known as the 'Seven sisters'. The Half-Moon Battery was also the original home of the castle's famous 'One o'clock gun', a gun that is fired at 1pm almost every day.

Edinburgh castle itself, is the most popular paid tourist attraction in Scotland. It is built on castle rock, a large volcanic rock that raises the castle high up to dominate the city's skyline. It has been involved in many armed conflicts between the Scottish and the English. The castle was a Royal residence until the unification of Scotland and England in 1603.