It goes without saying that making even the most simple movie is a massive undertaking, both in terms of time and money, and so it isn't something that filmmakers tend to dive into lightly.
But that doesn't mean there isn't room for outside-the-box artists to effectively approach movies as elaborate, costly experiments, testing the bounds of both themselves and cinema as a medium in the process.
These 10 films were all made as "what if?" challenges, where directors were more interested in seeing whether their bonkers idea could actually work rather than being confident that it would.
From sacrilegious remakes of unassailable classics to ground-breaking divergences from stylistic and narrative form, these 10 films were all bold provocations in their own way.
Whether they turned out successfully or not, you have to admire the daring on display, especially given some of the ludicrous filmmaking and acting talent on offer.
In an increasingly risk-averse, safe-playing Hollywood, this left-field bravery needs to be commended and championed, even when it doesn't always work...