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It's been over 100 years since the first public radio broadcast in history took place. The sound of a live opera featuring some of the most renowned opera singers of the time was broadcast from the Metropolitan Opera House.

Radio as a means of mass communication is one of the oldest, but it is still a huge part of our lives today, and Public Radio Broadcasting Day is the perfect time to appreciate the evolution of broadcast technology. Click through this gallery to learn more about the radio.

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According to the Daily Express, the first radio developments were called "wireless telegraphy."

▲The word "broadcasting" used to be an agricultural term for the process of spreading seeds.

▲Radio waves and radio transmissions were predicted by James Clark Maxwell in the 1860s.

▲From 1922 to 1971, you couldn't legally listen to radio in the UK without a license.

▲The Italian man was the greatest pioneer in long-distance radio transmission. Fun fact: he was the great-grandson of John Jameson, the founder of Jameson Irish Whiskey.

▲Marconi was responsible for the first successful transatlantic transmissions of radio waves.

▲Marconi won the Nobel Prize in Physics for his "contributions to the development of wireless telegraphy" in 1909.

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Nikola Tesla (pictured), Oliver Lodge, and Heinrich Hertz all claimed they invented radio transmission.

▲FM radio first came about in 1939.

▲For awhile, radio was the biggest mass communication method. Its influence was undeniable, which was later proven by broadcaster Orson Welles (who went on to become a renowned film director).

▲On October 30, 1938, CBS interrupted its music schedule to announce the news of an alleged alien invasion.

▲Sold as "extraordinary news," the show was in fact just the beginning of a radio theater play.

▲The show not only helped CBS beat their competitor NBC, but it also spread panic across several American cities.

▲The panic wave mainly hit locations near New Jersey, from where CBS transmitted the news and being the place where the alleged invasion was happening. Crowds fled en mass, and the story also left many residents in New York desperate.

▲The way the script was read followed the normal journalistic characteristics of the time, hence why it confused the listeners.

▲The dramatic story also included foreign press, interviews with witnesses, opinions from experts and authorities, sound effects, screams, and emotional broadcasters and commentators. Everything about it made it look like it was being recorded live!

▲The Daily News' front page the next day read: "FAKE WAR ON RADIO SPREADS PANIC OVER U.S."

▲The "Martian invasion" only lasted for about an hour, but it definitely shaped the history of radio.

▲Norway was the first country in the world to end FM radio transmissions.

▲The disconnection happened on January 11, 2017, in the city of Bodø.

▲The Norwegian government estimated the digitization of national radio stations will result in an annual profit of US$25 million.

▲The cost of using national FM radio transmission is eight times greater than using Digital Audio Broadcasting, the government explained.

▲There are an estimated 44,000 radio stations around the world, according to UNESCO. Radio is the biggest source of music in the media world.

▲Pittsburgh radio station KDKA was the first commercial station in the world to go live in 1920.

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In 2016, radio stations generated a total profit of almost $15 billion in the US, with $810 million coming from online radio, according to Statista.