After years of negotiations, the world breathed a collective sigh of relief as the Partial Nuclear Test Ban Treaty finally came into effect, outlawing nuclear explosions in the atmosphere, outer space, and underwater. With the ink barely dry on the signatures of over 100 countries, including the US, UK, and USSR, this historic agreement marked a major milestone in the pursuit of nuclear disarmament. By prohibiting above-ground nuclear tests, the treaty effectively ended the specter of radioactive fallout threatening humanity, paving the way for further non-proliferation agreements and a safer, more stable world.