This is a Hubble Space telescope image of Keyhole Nebula, also known as NGC 3372. The image shows previously unseen details of a mysterious, complex structure within the nebula. The Kehole Nebula is part of a larger nebula known as the Carine nebula, with an overall diameter of more than 200 light-years. It is one of the most outstanding features of the Milky Way in the southern hemisphere. The diameter of the Keyhole ring structure shown here is about 7 light-years. The nebula was formed by the dying star Eta Carina.