Buckling of shells: from fullerene to ping-pong ball Deformation of a spherical shell adhering onto a substrate due to van der Waals attractive interaction is investigated by means of numerical minimization. The configuration of the deformed shell is governed by the two dimensionless parameters, i.e., C_s/epsilon and C_b/epsilon where C_s and C_b are respectively the stretching and the bending constants, and epsilon is the is the depth of the van der Waals potential. As C_b/epsilon is varied systematically, we find both discontinuous and continuous bucking transitions for large and small C_s/epsilon, respectively, which is analogous to van der Waals liquids or gels. Some scaling arguments are employed to explain the adhesion induced buckling of spherical shells.