What is the purpose of a sundial?

A sundial is a device used to tell time by tracking the position of the Sun. It consists of a flat surface marked with hour lines and a gnomon, which casts a shadow onto the surface. As the Sun moves across the sky, the shadow changes position, indicating the time of day. Sundials were widely used in ancient civilisations, such as Egypt, Greece, and Rome, before the invention of mechanical clocks. They remain a symbol of timekeeping and are often seen in gardens or historical sites as decorative and educational tools.