The first great invention was one that is stil very important today—— the wheel. This made it easier to carry heavy things and to travel long distances. for hundreds of years after that there were few inventions that had as much effect as the wheel. Then in the early 1800's the world started to change. There was little unknown land left in the world. People did not have toexplore much anymore. They began to work instead to make life better. In the second half of the 19th century many great inventions were made. Among them were the camera, the electric light and the radio. These all became a big part of our life today.