I will  review the story of the SN 1987A explosion that occurred in the
Large Magellanic Cloud more than 20 years ago and is still the subject
of many detailed investigations.  I will show that although this supernova
was  somewhat peculiar, the study of SN 1987A has clarified quite a
number of important aspects of the nature and the properties of
supernovae  in general, such as the confirmation of the core collapse of a
massive  star as the cause of the explosion, as well the confirmation that
the decays of radioactive $^{56}$Ni and $^{44}$Ti are the main sources  of
the energy radiated at early and at late times, respectively.  Still we have
not been able to ascertain unambiguously whether the progenitor was  a
single star or a binary system, nor have we been able to detect the stellar
remnant, a neutron star that should have been produced in the core collapse
process.