 The three largest galaxies in our local group are the Milky Way, Andromeda, and Triangulum. This Hubble Space Telescope visualization of a computer simulation depicts their joint evolution over the next several billion years and ends with the massive collision between the Milky Way and Andromeda. Hubble observations indicate that the two galaxies orbiting the local group's center of gravity will impact each other in a head-on collision around four to four and a half billion years from now. On the first pass, the thin disk shapes of these spiral galaxies will be strongly distorted by the encounter. Subsequent passes will turn the two spiral galaxies into one giant elliptical galaxy. Their cores will merge along with their central supermassive black holes. The Triangulum galaxy will continue to orbit the merged pair through the end of this computer simulation, although other computer models show it joining the collision.