The Lagoon Nebula (also known as M8 and NGC 6523) is a giant interstellar cloud, classified as an emission nebula and H II region, in the constellation Sagittarius. At an estimated distance of 4,100 light-years, the Lagoon is one of only two star-forming nebulae faintly visible to the naked eye from mid-northern latitudes. In binoculars, the Lagoon is a distinct oval cloudlike patch with a definite core, like a pale celestial flower. The nebula has a fragile star cluster superimposed on it, making this one of the leading celestial sights of summer night skies.