There have been many great inventions that changed the way we live. The first great invention was one that is still very important today----wheel. This made it easier to carry heavy things and to travel long distance. For hundreds of years after that there were few inventions that as important as the wheel. Then in the early 1800's the world started to change. There was little unknown land left in the world. People didn't have to explore much any more.In the second half of the 19th century many great inventions were made.Among then were camera,the electric light and the radio. These all become a big part of our life today.the first part of the 20th century ---- more great inventions:the helicopter in 1909;movies with sound in 1926;the computer in 1928 and the jet plane in 1930.the middle part of the 20th century brought new ways to help people---diseases.they made peole healthier and live---.by this time most people had a very good life.