Contrary to the general belief that a black hole has only an event horizon and a singularity it is shown that it has a structure. The structure of a black hole is worked out using Schwarzschild interior solution. It is shown that there is an attraction towards the centre of the distribution when the radius r of the sphere is greater than 9m /4 where m= GM/c2 , M being the mass of the distribution of matter. When the radius is between 9m /4 and 2m the attraction is replaced by a repulsion first at the centre and then in a core gradually increasing in radius up to 2m. The matter is repelled towards the surface ending up with a spherical shell of radius 2m and of infinite density, forming a black hole.