Noel Marshall and Tippi Hedren, you see, were the very special kind of psychopathic eccentrics you only get among the wealthy elite of California. After a trip to Mozambique in 1969, they were inspired by the plight of the local lion populations to make a movie in tribute to the wonderful animals, showcasing how peaceable and not-actually-threatening lions really were. And taking further inspiration from the sight of an abandoned plantation villa that had become the den for a lion pride, they decided that this film would substantially involve lions puttering about a human habitation, while the humans involved did their best to stay out of the way. Somewhere along the film's seven-year path from conception to shooting, Marshall and Hedren realized they could both substantially increase their feline cast and do the good work of helping threatened animals by collecting abandoned lions, tigers, leopard, pumas, elephants (!), and flamingos (!!), and letting them wander loose on the ranch the couple bought just for the purpose. Thus they'd have not just a memorable and important film bringing public attention to the importance of conserving and protecting the big cats, they'd also have a preserve all ready to go (and Hedren has, to her great credit, devoted much of her life in the years since to carrying out that mission, turning the ranch into the Shambala Preserve, maintained by the Roar Foundation).
Anyway, this didn't happen, because to the non-surprise of just about every living human not named Noel Marshall and Tippi Hedren, putting a film crew in the middle of 150 largely untrained big cats is unbelievably goddamn dangerous. Shooting Roar stretched out from a scheduled six months to over four years, as a simply tremendous number of crew members and virtually all of the cast suffered injuries from lacerations and scrapes to Jan de Bont being literally scalped by a lion, requiring 220 stitches (in one of the most inspiring and/or mentally deranged "the show must go on" stories in history, de Bont returned to the production after recovering). Flooding, disease, and fires all took their toll on the feline cast, and there was, you will be just stunned to learn, an abnormally large amount of crew turnover as people began refusing to come back to set. Nobody died, which is both good and tremendously surprising.