Sydney • Fort Denison

In the nineteenth century, accurate timekeeping was essential for maritime navigation. To allow ships' chronometers to be synchronized, many ports installed a so-called Time Ball. Shortly before 1:00 p.m., the ball was raised to the top of a mast and then dropped precisely at 1:00 p.m. Sailors could use the moment of its descent to check their chronometers, enabling more accurate determination of longitude at sea. The Sydney Time Ball is one of the few remaining examples in the world that is still operated daily.