Over the centuries, people have developed various ways of telling the time. First, about 5,500 years ago, the Egyptians invented the sun clock. Next, about 3,500 years ago, the Egyptians made a sundial. Then, the Egyptians used water clocks about 3,400 years ago. After that, In the thirteenth century, the power-driven clock was invented. In 1927, the firstly quartz clock was developed. Lately, more recently, in 1956, came the digital clock.