Most galaxies live alongside neighbours, ranging from pairs and triplets all the way up to clusters of several thousands. Unfortunately, neighbours can sometimes get too close. When two galaxies approach, gravity can take over, pulling the pair closer till they collide and merge. These collisions produce spectacular displays of deformed and twisted shapes -- but what creates these contortions? In billions of years our own Milky Way galaxy is predicted to collide with our neighbour Andromeda -- what can future dwellers of the Solar System expect? Today, astrophysicists (including myself) are looking for signs of ancient galaxy collisions, which occurred billions of years in the past, and I'll describe why these ancient collisions are so vital to our understanding of the Universe.