Radio galaxies continue to play an important role in cosmological debates. <br /><br />
They are hosted by massive elliptical galaxies, and their high luminosities <br /><br />
allow them to be detected across a large range in redshift. <br /><br />
In this colloquium I will describe results from an investigation into the <br /><br />
properties of the warm ionized gas in the interstellar medium of radio galaxies <br /><br />
at high-z (z>2). We find evidence that this warm ionized gas is in infall towards <br /><br />
the AGN or host galaxy. Some implications will be discussed.