In the 1930s, the world was drawing closer and closer to a second global war. Radio broadcasts were constantly being interrupted to bring news of what was happening near and far. Technology was also rapidly evolving, with space travel looming on the horizon. And science fiction was emerging as a literary genre. So maybe it wasn't too surprising when, on Oct. 30, 1938, thousands and thousands of Americans believed Martians were invading the United States. Why shouldn't they? They'd been listening to the radio, when the program was interrupted by a news bulletin that Martians had landed in New Jersey and were preparing to attack [source: Lovgen].
Panic ensued, as people tried to figure out whether, and where, to flee, and how to protect themselves from the poisonous gas the Martians were said to be releasing in New Jersey. People jammed the roads. Hid in their homes. Armed themselves. Some collapsed and received treatment for shock and hysteria [source: Lovgen].
But, of course, no Martians had landed. The program, narrated by writer-director Orson Welles, was merely a radio play based on H.G. Wells' 1898 book The War of the Worlds. Before the play began, CBS Radio announced it was a play based on Wells' novel. But many listeners had tuned in while the broadcast was in progress, and therefore missed the explanatory introduction. Some estimates say 20 percent of listeners believed in the invasion, or somewhere around 1 million people [source: Lovgen].