The bright diffuse nebula NGC 3372 in Carina, about 2° across, containing numerous stars and clusters. It is divided into two parts by a dark V-shaped lane. At its heart is the variable star Eta Carinae, which is concealed by the smaller Homunculus Nebula. The Eta Carinae Nebula contains the Keyhole Nebula, a smaller dark nebula silhouetted against the brighter background near Eta Carinae. Its distance is about 7500 l.y.