Edinburgh Castle is now a ceremonial post. The New Barracks contain both the Governor's House, which serves as the Officers' Mess, and the Regimental Headquarters of the Royal Regiment of Scotland. The Army retains responsibility for these and for the Royal Scots Museum and Royal Scots Dragoon Guards Museum. Military tattoo A series of performances known as the Edinburgh Military Tattoo (since 2010 the Royal Edinburgh Military Tattoo) takes place on the Esplanade each year during August. The basis of each performance is a parade of the massed pipes and drums of the Scottish regiments, and since its inception in 1950 the tattoo has developed a complex format that includes a variety of performers invited from around the world, although still with a largely military focus. The climax of the evening is the lone piper on the castle battlements, playing a pibroch in memory of dead comrades-in-arms, followed by massed bands joining in a medley of traditional Scottish tunes. The tattoo attracts an annual audience of around 217,000 people, and is broadcast in some 30 countries to a television audience estimated at 100 million. One O'Clock Gun The One O'Clock Gun is a time signal, fired every day at precisely one p.m., excepting Sunday, Good Friday and Christmas Day. The 'Time Gun' was established in 1861 as a time signal for ships in the harbour of Leith and the Firth of Forth, away. It complemented the 'Time Ball', which was installed on the Nelson Monument in 1852, but was useless as a visual signal in foggy weather. Because sound travels relatively slowly (approximately ), a map was produced in 1861 to show the actual time when the sound of the gun would be heard at various locations across Edinburgh. The original gun was an 18-pound muzzle-loading cannon, which needed four men to load, and was fired from the Half Moon Battery. This was replaced in 1913 by a 32-pound breech-loader, and in May 1952 by a 25-pound Howitzer. The present One O'Clock Gun is an L118 Light Gun, brought into service on 30 November 2001. On Sunday 2 April 1916, at an unknown time of day, the One O'Clock Gun was fired in vain at a German Zeppelin during an air raid, the gun's only known use in war. The gun is now fired from Mill's Mount Battery, on the north face of the castle, by the District Gunner from