The Milky Way, our home galaxy, is a faint band of light that stretches across the night sky. Even the ancient Greeks dreamed of understanding their mysteries. After collisions with other galaxies, the Milky Way evolved in countless growth spurts. Recently, thanks to state-of-the-art space telescopes, we have been able to unveil its dramatic story. And also predict their disastrous future. Seen from the outside, the Milky Way is a disk of 400billion stars. We are only just beginning to understand the place of the Milky Way in a universe containing trillions of other galaxies. Over billions of years, our Milky Way made use of neighboring galaxies, adding countless new stars and triggering great epochs of creation. However, another clash is imminent. Another galaxy, Andromeda, is hurtling straight toward us, challenging the long-term fate of the Milky Way.