OpenAI has solved part C of the Navier-Stokes Millennium Prize Problem—one of seven unsolved mathematical challenges worth $1 million each. Using swarms of AI agents, they proved that smooth fluids can develop singularities (infinite velocity) in finite time under smooth forcing, answering a 90-year-old question. This breakthrough demonstrates multi-agent AI collaboration and has implications for understanding fluid dynamics across aerospace, weather prediction, and medicine—though the full prize still requires solving other sub-problems.