I think the greatest invention is "The internet". Most people use the internet everyday. With computers and smart phones, we read internet news, check e-mail, blog and so on. Everything is possible with the internet.
Before the invention of the internet, we could only get information from all over the world through the television or radio. However television and radio are one-way communication systems. We just watch television, listen to the radio and that's all. However, with the internet, we can experience a two-way communication system. For example, after we read internet news, we can write a comment about that news. We can express our opinion, and also read other people's opinions.
Also, the internet makes us more comfortable. For example, I want to go on a trip abroad. First, I will serch for information using google or naver, about accomodations, food, places and so on. Next, I will book the flight and hotel through the internet. If I couldn't use the internet, I would have to find many books for that information, and I would have to call the airline and hotel for a reservation. It is more inconvenient than using the internet, and also needs more time. Using the internet, we can shop, take a class(cyber class), use internet banking etc. We can't imagine living without the internet anymore.
