The Birds wasn’t pure fiction. In 1961, hundreds of seabirds in Capitola, California began slamming into buildings and cars, leaving residents terrified. 

Scientists later found the birds had ingested toxin-producing algae that made them disoriented and aggressive. 

The incident, combined with the eerie 1952 short story The Birds by Daphne du Maurier, inspired Alfred Hitchcock to turn the chaos into one of the most chilling films of its time.