Fresh from the success of 1974’s The Godfather Part II, for his next movie, Francis Ford Coppola embarked on one of the most challenging movie shoots in cinema history.

To say that he put a lot on the line when it came to filming his Vietnam War epic Apocalypse Now in 1976 would be putting it lightly. Initially estimating a budget of $2 million, he ended up putting more than $30 million of his own money into the project, using the deeds to his home and his Napa Valley winery as collateral.

That would have been stressful enough for any director, but Coppola’s decision to shoot the movie on location in Southeast Asia—to give it as authentic a jungle-based setting as possible—didn’t exactly help matters either.

A 14-week filming schedule was announced, and a series of lavish sets were built on location in the Philippines. But just before filming was due to begin, Typhoon Olga swept through the islands in the summer of 1976 and destroyed millions of dollars of work. Production was forced to shut down for two months—and even then, that wasn’t the worst thing that happened.

Problems accessing US military equipment for the movie further delayed the shoot, and in the real-life jungle location, several cast and crew members fell ill. The interest charged on Coppola’s loans skyrocketed to almost 30%, and the stress of the shoot coupled with the risk of financial ruin led to him suffering an epileptic seizure, a near-fatal heart attack, and eventually a nervous breakdown on set. Filming staggered on until May 1977—more than 40 weeks over schedule—while post-production went on to take a further two years.

Eventually, the movie arrived in cinemas in August 1979, and despite initially lukewarm reviews went on to gross more than $150 million and is today considered a landmark war movie. Coppola’s immense gamble had finally paid off.