Most people only think of Hell as a place or experience after death and give little thought to it as a present reality. I think that in the minds of the Biblical authors it was the exact opposite.
Jesus only implies that Hell existed after death (he uses hyperbolic imagery alluding to this in only one parable and it's really nonexistent throughout the rest of his teachings). But He talked about hell all the time. Now, for Jesus hell always had to do with how we live. If we don't love, if we don't take care of the poor, if we're not generous, etc. we end up in hell. I think that this is because for Jesus hell was very practical. The world becomes hell when we don't live like we're supposed to. If we don't care, if we're not generous, if we don't love, then hell comes crashing into earth... people are denied life to the fullest (which is what Jesus came to bring).
Hell is the place where life doesn't exist... where chaos rules. Take the holocaust for example... if that's not hell, what is? In the holocaust people were denied life and chaos was overwhelming.
Another hint that hell might be here is that the word Jesus used for Hell is here. Jesus used the word "Gehennah" which is actually a place outside of Jerusalem which was an infamous dump where, during the great famine, bodies were allegedly taken to be burned. Gehennah came to be called "The place of whipping and gnashing of teeth where the fire never dies." Gehennah was powerful language to imply suffering (people who suffered greatly ended up there).
I do believe that hell is eternal but before we start thinking about the eternity after death we should focus on this side of eternity... the eternity in our own backyard. We can bring hell OR heaven crashing down to earth.