Depending on where (and when) you look in our Universe, radio emission from active galaxies is either rare (~1 in 10 for field galaxies) or commonplace (almost 100% in the centers of dense clusters of galaxies at low redshifts). I will discuss what triggers the radio emission, how the growth of the radio source is influenced by its environment, and how it in turn can have a profound effect on the host galaxy. It is becoming well established that some form of feedback mechanism regulates the fuel supplied to the central dominant AGN in galaxy clusters. Details of the accretion and the energy transport are still to be understood and are important for the study of not just clusters, but galaxy evolution as well. By studying the radio emission of the central dominant AGN over a broad range of physical scales we can read the history of energy input to the cluster. I will describe some of the radio observations from parsec to mega-parsec scales. Low frequency observations are of particular interest to explore these problems, and I will spend some time describing the Long Wavelength Array that we are currently building in New Mexico.