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Arago's spot is a classical example of a beautiful mathematical theory anticipating a beautiful physical fact. Back in the 1800s, the scientific community was debating between defining light as a particle or a wave. Young's experiments, which demonstrated the wave-like characteristics of light, paved the way for Fresnel to formulate a mathematical wave theory. When Fresnel presented his theory in a competition, it came under scrutiny by Poisson, an advocate for the particle theory. In his eagerness to debunk Fresnel's work, Poisson delved into the mathematics and discovered a prediction by the theory which he thought was inconsistent with experiments: shining light on an opaque disk should yield a bright spot at the center of its shadow. Remarkably, no one had tested this prediction before. Motivated by Poisson's finding, Arago executed the experiment, and indeed, the spot manifested. What was intended as Poisson's rebuttal to the wave theory unexpectedly became a powerful testament to light's wave-like behavior.