Every War Of The Worlds Adaptation: Ranked Worst To Best
1. The Radio Play
Yes, this is kind of cheating as this is supposed to be a list of screen adaptations and consideration hasn't been given to other versions from the radio or other sources, but you'd be annoyed if this wasn't here.
Besides, Orson Welles' 1938 radio drama produced such an iconic reaction that the audience response in itself inspired multiple movies: the TV films The Night America Trembled in 1957 and The Night That Panicked America in 1975, and the indie comedy Brave New Jersey in 2016.
There will always be debate about the extent to which radio audiences were genuinely fooled by Welles' faux newscasts of a Martian landing in Grover's Mill, New Jersey, but it was certainly a powerful and effective way of conveying the alien invasion concept with the immediacy of contemporary technology. It became hugely influential on anything later that would use a faux-news or documentary style, not just in adapting The War Of The Worlds, but across all stories and media.
The newscasts only make up roughly the first half of the show, though, the rest is a fairly conventional radio drama. And, even stripped of the context of mass panic, it's still an impressively engaging, gripping thrill ride that, eighty years after the fact, also remains a fascinating window into that time and place.