Dissociative recombination of molecular ions with electrons is the most important neutralising process in a plasma cold enough to contain molecules. The basic features of recombination of diatomic molecular ions are by now quite well explained, whereas recombination of polyatomic ions is much less well understood. Experiments during the last five years at ion storage rings have shown that triatomic molecular ions tend to break up into three atoms upon recombination with electrons. Very recently the question of how this break-up occurs has started to be addressed by the use of particle imaging techniques at ion storage rings. In this article we will discuss results for H2O+ and H3+.