The Crescent Nebula (NGC 6888) is an emission nebula located in the constellation Cygnus, roughly 5,000 light-years away. It was formed by the powerful stellar winds of a massive Wolf-Rayet star (WR 136), which is nearing the end of its life. As the star shed material during an earlier red supergiant phase, the subsequent fast winds collided with the older, slower-moving gas, creating a shell of glowing hydrogen and oxygen gas. This interaction gives the nebula its distinctive crescent shape, spanning about 25 light-years across. The nebula glows brightly in Hα and O III emissions, with complex filamentary structures visible in high-resolution images. NGC 6888 offers astronomers a close-up look at the life cycle of massive stars and the processes that precede a supernova explosion, making it a highly studied and visually striking deep-sky object.