The radio transmits sound and information over long distances using electromagnetic waves. A transmitter sends radio signals that are picked up by a receiver. Experimental work in the 1820s led to the development of electromagnetic theory and the first radio transmission in 1887. In 1895, Guglielmo Marconi invented the wireless telegraph, known as the radio. The radio transformed society by allowing mass communication and the spread of ideas worldwide. However, radio listening has declined due to the rise of technologies like social media that allow people to create and share their own content.