The Sudbury Neutrino Observatory (SNO) is a unique scientific facility located in Sudbury, Ontario, Canada. It was designed to study neutrinos, which are tiny, nearly massless particles produced in nuclear reactions, such as those occurring in the Sun. SNO is situated 2,000 meters underground to shield it from cosmic radiation, allowing for more accurate measurements of neutrino interactions. SNO made significant contributions to our understanding of neutrino oscillation, a phenomenon where neutrinos change types as they travel. This research helped confirm that neutrinos have mass, which was a groundbreaking discovery in particle physics and contributed to the broader field of astrophysics.