  The Nobel Prize in Physics 2020 has been divided, one half awarded to Roger
Penrose for the discovery that black hole formation is a robust prediction of
the general theory of relativity. and the other half jointly to Reinhard Genzel
and Andrea Ghez for the discovery of a supermassive compact object at the
centre of our galaxy. Here we describe their work and put it in historical
context and discuss specific advances that have been rewarded.
