The universe may feature large-scale inhomogeneities and isotropies that cannot be explained by the standard model of cosmology. After reviewing present observational constraints on inhomogeneity around us, I will present the BEHOMO project (Cosmology BEyond HOMOgeneity and Isotropy), whose aim is to study, via numerical cosmology methods, the evolution of the large-scale structure on an inhomogeneous background. I will describe the BEHOMO suite of 68 simulations and data products, and I will present the preliminary results regarding the growth of structures. Specifically, I will show that the zero-shear approximation is able to accurately describe the angular power spectrum of the simulations that have mildly nonlinear LTB structures.