The questions about the life, the Universe (the sfere of knowledge that's becoming bigger and bigger as we know more and more about our world and the worlds sorrounding us), why are we here, are not new. They were put by many generation of man from the beginning of time and the answers varied. A lot. The great number of religions extisting now or extinct over the last fi ve thousand years is a valid proof that there is no universal answer but different answers, each for every person.
Where do we go when we die? The body goes to ground, as dirt or ashes or becomes meat for other animals, but what about the soul? What's happening with the souls, the memories of a liftime, the feelings? Are they lost?
Does our actions and our feelings in this life affect what happens to each of us when we die? Will we be punished or rewarded for that?
Christianity tries to responde to this sort of questions: yes, a righteous life (according to the Bible, their main book) will bring the Christian to heaven. His/her mistakes and faulty life, breaking the rules, will bring the believer to hell. The reward is for the faithful, according to Jesus, is to live etternaly with him in heaven.
Hell is a place and a destination of just and eternal torment for those beings, angelic or human, who rebel against God’s righteous rule. This sort of personally designed punishment was reminiscent of Greek mythology’s Tartarus, the place where Zeus flung the after claiming Mount Olympus. It was also known as the Pit, a place of pitch darkness, which was filled in with fires and demons in the Christian mytology.
In contrast the heaven is the dwelling place of God and a reward for those who receive God’s loving offer of salvation in Jesus Christ. After a life of obedience the Christian might (at least) expect a bit of rest: the mythology says that as he prepared to go to the cross Jesus promised those who trusted in him that he was going to prepare a place for them and not only for them but for all who would receive him as savior in the future. The Bible mentions instruments (as violins, harps and pipes) and fruit trees when describing the non-earthly realm. It is considered that angels are living in hell, protecting the humans below during their lives.
Hell and heaven are core belief in the Christian faith: they represent the two ways in wich the Christian God upholds the righteous judgments when Jesus Christ returns to the Earth. They (the Christians) say that God is honored both in heaven and hell, but in different ways.