HiRISE: Triple crater in Elysium Planitia

This image shows a triple impact crater in Elysium Planitia near Tartarus Montes, which probably formed when a binary—or even triple—asteroid struck the surface. (Binary asteroids orbit each other, while also orbiting the Sun). The two larger craters must have been produced by asteroids of approximately the same size, on the order of a few hundred meters across… [More at link]