CBS warned that Welles’ production was only a radio show, but it mirrored an actual news broadcast so accurately that the warnings were lost on most listeners.
War of the Worlds is broadcast on the radio
Horrified people all over the East Coast huddled by their radios and listened fearfully to the newscast of a Martian invasion of Earth. In Grover’s Mills, New Jersey, where the Martians had supposedly landed, people took to the streets with weapons, intent on repelling the invading army.
Soon a mob had assembled, and police were called to subdue the panicked crowd. But there were no Martians, only acting impresario Orson Welles’ overheated imagination. The entire "news broadcast" was only an adaptation of H.G. Well’s War of the Worlds, performed by Orson Welles’ Mercury Theatre and airing on CBS. Radio announcers were more careful to insert disclaimers during fictional programs after the War of the Worlds fiasco.