Deep beneath the mountains of Japan, a vast underground chamber housing 50,000 tons of ultra-pure water is working to uncover one of the universe’s most mysterious particles It's called Super-Kamiokande, and it was created to find neutrinos. These nearly invisible particles pass through matter undisturbed, making them notoriously difficult to study. But within this sci-fi-like facility, when a rare neutrino collides with a water molecule, it emits a faint, blue flash known as Cherenkov radiation. Thousands of sensitive light detectors lining the chamber’s walls capture these elusive signals, offering scientists a rare glimpse into the hidden workings of the universe. Since its construction, Super-Kamiokande has revolutionized our understanding of physics. In 1998, it provided the first solid evidence that neutrinos have mass, a discovery that challenged long-held theories and led to a Nobel Prize in 2015. Beyond groundbreaking discoveries, the facility also watches the cosmos for neutrinos from supernovae—exploding stars that forge the elements critical to life. Through these glimpses into the unseen, Super-Kamiokande continues to illuminate the deepest mysteries of space, time, and matter.