The new world atlas of artificial night sky brightness reveals that over 80% of the world's population and more than 99% of the U.S. and European populations live under light-polluted skies. The Milky Way is hidden from over one-third of humanity, including 60% of Europeans and nearly 80% of North Americans. Light pollution significantly affects the visibility of the night sky, with 23% of the world's land surfaces between 75°N and 60°S, 88% of Europe, and almost half of the U.S. experiencing light-polluted nights. The atlas uses high-resolution satellite data and precision sky brightness measurements to quantify light pollution globally. It shows that light pollution is a pervasive environmental issue, affecting even pristine areas. The atlas also highlights the impact of light pollution on human health, ecology, and culture. The study emphasizes the need for immediate action to reduce light pollution, as it has serious consequences for biodiversity, public health, and energy waste. Techniques to reduce light pollution are already known and being implemented in various regions. The atlas provides a comprehensive view of light pollution levels worldwide, showing that light pollution is a global problem with significant implications for human and environmental well-being. The study underscores the importance of addressing light pollution to preserve the night sky and protect natural ecosystems.The new world atlas of artificial night sky brightness reveals that over 80% of the world's population and more than 99% of the U.S. and European populations live under light-polluted skies. The Milky Way is hidden from over one-third of humanity, including 60% of Europeans and nearly 80% of North Americans. Light pollution significantly affects the visibility of the night sky, with 23% of the world's land surfaces between 75°N and 60°S, 88% of Europe, and almost half of the U.S. experiencing light-polluted nights. The atlas uses high-resolution satellite data and precision sky brightness measurements to quantify light pollution globally. It shows that light pollution is a pervasive environmental issue, affecting even pristine areas. The atlas also highlights the impact of light pollution on human health, ecology, and culture. The study emphasizes the need for immediate action to reduce light pollution, as it has serious consequences for biodiversity, public health, and energy waste. Techniques to reduce light pollution are already known and being implemented in various regions. The atlas provides a comprehensive view of light pollution levels worldwide, showing that light pollution is a global problem with significant implications for human and environmental well-being. The study underscores the importance of addressing light pollution to preserve the night sky and protect natural ecosystems.