The numerical prediction of the flow around a smooth cylinder is one the classical test cases of Computational Fluid Dynamics (CFD). Different mathematical models have been used to address this statistically periodic flow. Namely, ensemble-averaged Navier-Stokes equations (URANS); partially-averaged Navier-Stokes equations (PANS); space filtered Navier-Stokes equations (large eddy-simulation LES or variational multi-scale VMS) and direct solution of the Navier-Stokes equation (DNS). Although all these models deal with turbulence in a very different way, all of them require a numerical solution and so they all require a careful control of the numerical uncertainty. We present an overall view of the values of the average drag coefficient that have been published in the open literature, which shows a worrying spread of data. In this paper, we present Solution Verification exercises for the simplest model of those mentioned above: URANS.