Egypt

The Egyptians, by 2100 BC, had invented a means to divide the day into 24 hours using sundials or shadow clocks to measure the time of day. The Sundial indicates the time of day by the positioning of the shadow of some object on which the sun's rays fall. The shadow clock consists of a straight base with a raised crosspiece at one end. A scale with time divisions is inscribed on the base. The clock is set east-west and is reversed at midday.
The Egyptians also divided the day into 12 parts as well. They used huge granite columns called Cleopatra Needles, a trio of obelisks, to keep track of time periods. They had 12 marks on the ground that equalled 12 parts of the day. When the sun touched the top, a shadow was created and the length and position of the shadow told the Egyptians how much daylight remained. They invented a portable piece called a sundial. It contains 3 parts: a circular dial, a needle and a style (gnomon) to keep the needle in place. Cleopatra's needles were inconvient and impractical for the average person.