Time guns

original citadel of St. Petersburg, Russia

thumb|The Janiculum Hill seen from NE. At lower left, the church of San Pietro in Montorio. At lower center, the Academia de España in Rome. At middle right, the Acqua Paola. At top center, the roof of the American Academy in Rome. The Janiculum ( ; ), occasionally known as the Janiculan Hill, is a hill in western Rome, Italy. Although it is the second-tallest hill (the tallest being Monte Mario) in the contemporary city of Rome, the Janiculum does not figure among the proverbial Seven Hills of Rome, being west of the Tiber and outside the boundaries of the ancient city.

astronomical observatory in Sydney, New South Wales, Australia

sundial equipped with a cannon which fires at noon

island castle in Guernsey

Time signal gun in Hong Kong

heritage-listed former penal site and defensive facility in Sydney Harbour, Australia

fort and military museum in Halifax, Canada

Croatian cannon

historic time signal in Cape Town, South Africa since 1806