Edinburgh Castle dominates the city centre, sitting astride the core of an extinct volcano, its three sides scoured almost vertical by glacial action. Although the castle looks impregnable, it often changed hands between the Scots and English throughout the centuries.
The place has seen plenty of action: back in the 6th century it was used as a defence against the Picts, while in the 18th century Bonnie Prince Charlie's army tried but failed to breach its walls. These days hostilities are more likely to erupt between competing tour groups.
By the mid-18th century, the castle looked much as it does today. Partly thanks to Sir Walter Scott, in the 19th century it began to recover its importance as a Scottish symbol.
Visitors enter from the Esplanade, a parade ground where the changing of the guard occurs on the hour. Sites within the castle proper include Mills Mount Battery, where a gun salute takes place on weekdays; St Margaret's Chapel, the oldest building in Edinburgh; the Palace, built between the 15th and 16th centuries; and the Scottish United Services Museum, which houses displays on the history of Scottish regiments.