My talk is meant as a simple and pedagogical introduction to the field of wave transport in disordered media. I will illustrate various related concepts by simply concentrating on light propagation in optically thick media. I will address the fate of interference in such systems and show that, in coherence-preserving media, interference can have a dramatic influence such as bringing propagation to complete halt (the celebrated Anderson localization mechanism). I will describe one of the most emblematic signature of interference effects in multiple scattering, the so-called coherent backscattering (CBS) peak. I will illustrate the influence of the "quantum nature" of the scatterers by discussing experiments done with resonant atoms. I will conclude by sketching some perspectives of potential interest.