The Schwarzschild metric is the solution of Einstein's equations for a spherically symmetric vacuum with a singularity at the origin. Schwarzschild came up with this solution only days before his death. The coordinates are flawed, as they contain a coordinate singularity at r = 2m, the event horizon of the black hole. This was not commonly recognized as a coordinate singularity until after the deaths of both Einstein and Schwarzschild, although it is suspected that Eddington understood this. The problem is fixed by a coordinate transformation to Kruskal coordinates, in which the metric is perfectly well-behaved at the event horizon.