Open Water (2003) - $55 Million

Anxieties about the deep ocean were exploited perfectly by avid scuba divers and filmmakers Chris Kentis and Laura Lau. The terrifying survival tale follows an American couple on a tropical vacation who go on a group scuba diving excursion, only to be accidentally left behind in the middle of the ocean due to a lazy crew headcount, forcing them to fight dehydration, exhaustion, and an approaching school of predatory sharks. The hidden psychological terror focuses on the utter insignificance of human ego, vanity, and modern marital petty arguments when exposed to the brutal reality of nature, showing that as the couple bickers while floating helplessly, their superficial civilised lives are completely stripped away, leaving them to face the terrifying truth that the universe is entirely indifferent to their survival. Working completely independently on a tiny $120,000 budget, the husband-and-wife duo filmed the entire project using real, live sharks rather than digital effects. After a buzzy screening at the Sundance Film Festival, Lionsgate acquired the minimalist survival thriller, generating an incredible $55.5 million worldwide.