A hundred years ago, formulated as a revolutionary theory of physics, quantum mechanics enabled humanity to understand and even manipulate realms far beyond everyday experience and imagination. In this context, the groundbreaking ideas and methods that emerged have continued to unravel the mysteries of nature while lying at the heart of today’s advanced technologies. Quantum phenomena such as superposition and entanglement are at the forefront of a new technological revolution, enabling advances ranging from secure communication and quantum computing to next-generation sensing and precision measurement. At this Quantum Century event, we will together explore with high school students the hundred-year journey of quantum science, its profound contributions to modern technology, and the new horizons that await us in the coming century.