The Lagoon Nebula is known by a few other names: Messier 8, M8, and NGC 6523. This nebula is known as an emission nebula. It is one of only two star forming nebula that can be seen with the unaided eye in the northern latitudes. It is an interstellar cloud that is located in the Sagittarius constellation and it has an H II region. It was discovered by Guilliaume Le Gentil in 1747.