One of only two star-forming nebulae visible to the naked eye from mid-northern latitudes, the Lagoon lies 4,100 light-years away in Sagittarius. Its dark central lane — the ‘lagoon’ — is a dust lane silhouetted against the glowing gas behind it. The young open cluster NGC 6530, embedded within, is only a few million years old and its hot stars are the primary source of ionising radiation lighting up the nebula.