Strongly lensed supernovae: lessons learned

Since a few years, we have finally entered the era of discoveries of multiply-imaged gravitationally lensed supernovae. To date, all cluster lensed supernovae have been found from space, while those deflected by individual galaxies were identified with wide-field ground-based surveys through the magnification of "standard candles" method, i.e., without the need of spatially resolving the individual images. We review the challenges in identifying these extremely rare events, as well as the unique opportunities they offer for time-delay cosmography and the study of the properties of the deflecting bodies acting as lenses.