The supernova SN1987A in the Large Magellanic Cloud, together with new instrumentation like ALMA, offers an unprecedented opportunity to tackle fundamental issues of supernova explosions. Large masses of molecules and dust have been formed in its inner debris over the last 25 years. Recently developed tomographic techniques have allowed to obtain 3D-images of its molecular emission. Also, high-resolution images of dust emission have recently been obtained. All these results, compared with predictions from hydro-dynamical simulations, are paving the way to a better understanding of supernovae explosions. In the talk, the main results will be highlighted with emphasis on the advances produced in the last two years in the understanding of the structure of the inner ejecta.