Realkasa at 5 Calderese is a great place to stay in the center of Bologna. You are close to everything but without the noise. I slept very soundly in this great studio apartment. I was on a relatively long stay and grew to like the flat more and more. Everything works really well and the walls are thick so you do not hear the neighbors or the sounds of the street. I highly recommend this place to anyone wanting to experience living in Bologna, or for a brief visit.