Radio is a form of technology that makes it possible for us to hear sound coming from far away places. It was invented in the late 1800s, but it took several decades for it to be introduced and used in different countries around the world.
In the early 1900s, radio was first used in the United States and some parts of Europe. It quickly spread to other parts of Europe, including countries like France and Germany. By the 1920s, most people in those countries had their own radios.
The next country to get radio technology was Japan, in the 1930s. This was followed by most of Asia, including China and India, in the 1940s. During this time, almost all countries had access to radio.
In the 1950s, radio technology became even more widespread, with most of Africa, South America and the Middle East receiving it.
Since then, radio has become an essential part of everyday life in most countries of the world. You can now listen to the radio just about anywhere: in cars, on your phone, or even in some airplanes.