Everyone knows what went on in Valhalla. There, in Odin's hall, with its 540 doors, its walls made of spears, and its roof fashioned from shields, those Norsemen who had met glorious and violent deaths enjoyed banquets, battles, bragging and booze for the rest of eternity. But what became of the others - the poor souls who died of sickness or starvation, who came to an accidental end, or who simply passed away in old age? No feasting or fighting for them. Instead, they descended into Helheim.
And if that sounds like a play on words, then that's because the English word "hell" comes from the same root. Helheim was literally the "home of Hel", the monstrous daughter of the trickster god Loki. But there ends the similarity between Helheim and the flaming hell feared by some Christians.
For the lowest of the nine worlds of Norse mythology was a cold, dark, misty place that lay beneath the world of Niflheim, some distance to the north of Ginnungagap. Here the unfortunates who missed out on Valhalla remained for all time, trapped by the impassable river Gjoll and tormented by Hraesvelg the corpse-eater, whose giant wings chilled them with an icy blast.
More extreme versions of the here and now, Valhalla and Helheim are typical of the countless hereafters that humans have been busy dreaming up ever since the question was first asked: What becomes of us when we die? If your idea of fun is brawling and boasting, then the prospect of a seat at Odin's table is the ideal motivation for you. And if the greatest scourges of your time on earth are the darkness and cold of a northern winter, then the thought of shivering in Helheim might just keep you on your toes.
Cold underworlds abound in cold climates. In Inuit mythology, the souls of the dead are purified in a frozen wasteland called Adlivun, before travelling to the Land of the Moon where they find eternal peace. In Siberia, some groups still believe in an icy nether region inhabited by mud-eating mammoths and enormous rodents.
In the parched landscape bordering the Dead Sea, however, frost and fog are less of an inconvenience than in Scandinavia. So it's hardly surprising that the Jews envisaged an underworld that resembled the constantly burning rubbish pits on the edges of their towns.
According to some rabinnical teachings, Sheol - the word denotes a landfill site - was simply regarded as a place of purification where the dead were held for a year or so before joining God in Gan Eden, a paradise that resembled the Garden of Eden. Judaism has never placed much emphasis on the afterlife, and nowhere in Mosaic law is its existence explicitly acknowledged.
But Christianity was so taken with the notion that earthly wrongdoing would be punished in the hereafter, and virtue rewarded, that the idea of a hot, middle-eastern kind of hell took root even in northernmost Europe, along with a garden-like heaven in which the righteous delighted, not in feasting, but in the eternal presence of the Creator.
Nobody is sure where the English word "heaven" comes from, since it can be traced back equally convincingly to Gothic words meaning "cover" (heaven covers the Earth like a roof) or "home" (heaven is God's home). And if linguists disagree about its name, theologians still don't always see eye to eye about its location.
To many believers, God is everywhere, and by this token, it has been argued that heaven must also be everywhere. The general view, however, has been that God, the saints and the righteous, together with the angels (be they of normal size or so tiny that they might congregate on the head of a pin) reside in a special place outside the world, while retaining the option of unlimited free travel in the world.
And in heaven, the faithful will see God face to face, clearly and distinctly - a matter of some significance, apparently, since scholars and popes continue to argue about its implications. Given that mere humans are incapable of seeing the Almighty, does this mean that, on ascending to heaven, the righteous become supernatural? On this and other niceties, Rome is undecided. However, seeing God and being close to him is for many what getting to heaven is all about.
Beyond that, though, the Bible gives surprisingly little away concerning the nature of heaven. Aside from the strictly architectural fantasies of medieval woodcarvers, artistic representations down the ages have left us with little more than an impression of the righteous, carefully ranked in order of status, gazing with wonder at the source of divine light, while winged musicians blow trumpets, or provide a harped accompaniment to a perpetual act of worship.
Even the "pearly gates" of popular humour seem to have originated in a hymn of 1853 ("Oh! for the pearly gates of heaven! Oh! for the golden floor!"), and St Peter's supposed role as gatekeeper and chief keyholder is disputed by those who feel that it stems solely from a misreading of St Matthew's gospel (16, verses 19-20).
But if artists have felt less than inspired by the visual possibilities of paradise, they have had no such difficulties when it came to "the other place". In the Middle Ages, a prime role of image-makers was to teach God's children what punishments lay in store for them should they stumble from the path of righteousness, and it was a role they performed with unconcealed glee.
In cathedrals and churches across Europe, vast "doom" paintings, often covering an entire wall, depicted in the grossest detail the fate that awaits sinners at the Day of Judgment. Scaly-tailed demons prod and poke their hapless victims, playing to the crowd by reserving the lewdest indignities for wayward prelates and over-mighty nobles.
As in the visual arts, so in literature. William Blake, who at least included a few trees in his vision of heaven, commented in his illustrated edition of Paradise Lost that Milton "wrote in fetters when he wrote of angels and God, and at liberty when of devils and Hell", and put this imbalance down to Milton's being "a true poet and of the Devil's party without knowing it".
In his Divine Comedy, Dante delights in detailing the various categories of wrongdoer consigned to the inferno and its environs, listing among others the lustful, the gluttonous, the hoarders, the wrathful and the violent, along with murderers, robbers, plunderers, suicides, panderers, seducers and flatterers, those who betray their guests and those who harm nature.
Indeed, the question of who burns in hell and who qualifies for a place in paradise (the word was first use to describe the parks of Persian kings) has long divided Christians. For centuries, those who believe that faith alone opens the gates of heaven have slugged it out with those who insist that good works are also required. Meanwhile, the qualifications for eternal hellfire have been so hotly disputed as to divide Christendom into several warring factions. Perhaps in the interests of expedience, the Roman Catholic Church long ago interposed a third option between heaven and hell, namely purgatory, a place where sinners who have repented but not expiated their sins are sent for purging in readiness for their final ascent. It was the suggestion that this painful period of purging could be shortened by the mere purchase of "indulgences" that infuriated Martin Luther and so led eventually to the reformation.
Like the Eastern Orthodox Church, most protestants reject the notion of purgatory. The 16th-century Swiss reformer John Calvin argued not only that there were no halfway houses, but that only a predetermined "elect" were destined for salvation. In other words, the whole thing was cut and dried, rather as the non-elect would themselves be in due course.
What about unbaptised children, nonChristians, or good people whose only mistake was to have died before the resurrection? Hardliners of all persuasions condemn the lot of them to the flames, but the Catholic Church has long maintained, albeit unofficially, that such people are held in the suburbs of hell in a place called limbo until such time as the gates of heaven are flung open by Christ himself. The existence of a range of afterlife options features in many of the world's religions. The Quran speaks of seven heavens and seven hells, the highest resembling a luxurious desert oasis where Muslims are allowed activities which are forbidden on Earth, such as drinking wine. According to Brewer's Dictionary of Phrase and Fable, it is said of this seventh heaven that each inhabitant is larger than the earth and has 70,000 heads, each head with 70,000 faces, each face with 70,000 mouths and each mouth with 70,000 tongues, each of which praises the Most High in 70,000 languages. Lower, quieter heavens are fashioned out of precious materials - ruby, garnet, white gold, pearl and so on - and are presided over by an assortment of lesser personages, including Jesus, who is ranked below the prophet Enoch, and shares the second heaven with John the Baptist. Meanwhile, seventh hell is reserved for those who most blatantly reject God, and here they must endure a bed of fire with nothing to drink besides "a boiling fluid, and a fluid dark, murky, intensely cold".
For sheer complexity, the afterlife arrangements of classical mythology take some beating. The Greeks led the way, with an elaborate underworld geography, intertwined with the dread rivers Oceanus and Styx. Surprisingly for those who automatically think of paradise as "up there", this subterranean world even included Greek heaven. Elysium was where heroes continued their heroic exploits and the virtuous enjoyed an eternity of feasting, sport and assorted entertainments on the Elysian Fields.
In Greek as in many other mythologies, places and landscape features frequently double up as gods or other beings. The Styx river is the daughter of Oceanus, and is spoken of both as an active participant in the war against the Titans and as the stream and marsh of the same name across which the souls of the dead must be rowed by the ferryman Charon.
Similarly, Hades is the name that Homer gives to the god who reigns over the dead while, in later mythology, Hades is the name of the gloomy place where the spirits of the departed continue a flavourless, unhappy existence. Hades is not a place of punishment as such, and has been compared to Sheol, the Jewish rubbish-tip.
Tartarus is a place of punishment. The home of darkness and the place where all the waters originate and to which they return, it is the lowest abyss beneath the earth, so low that a brazen anvil falling down from Earth would take 10 days to reach it. Oh, and Tartarus is also the father of the monsters Echidna and Typhon.
Did the Ancient Greeks literally believe in these stories, in the way that modern fundamentalist Christians believe in the fires of hell? "It is not easy to believe that the gods possess any underground dwelling where the souls collect," wrote Pausanias in his Description of Greece, and Socrates asked: "Who knows if to live is to be dead, and to be dead, to live? And we really, it may be, are dead; in fact I once heard sages say that we are now dead, and the body is our tomb."
If the Ancient Egyptians harboured such doubts about the afterlife, you wouldn't know it from the amount of toil and expense that went into their preparations for it. Their mythology changed considerably over 3,000 years, as did the names of the various regions supposedly inhabited by the dead, but belief in heaven and hell remained a common factor throughout.
In one version, the newly deceased were welcomed to Ament, the underworld, by a goddess of the same name. Their hearts or spirits were then weighed against the feather of truth, and those found wanting were consumed by a female demon, part lion, part hippo and part crocodile, who lived beneath the scales. Those who passed the test proceeded to Aaru, a series of paradisiacal islands covered not with gold, but with something arguably more valuable to a people raised in desert conditions: wheatfields.
Alongside their well-to-do dead, the Egyptians buried such provisions, clothing and equipment as might be needed in the afterlife, and replicas of servants were sent along for the ride in the hope that they would be converted into fully-functioning employees in the hereafter. A similar belief in the need for personal assets to be transferred into the next life led the ancient Aryans to burn a man's widow alongside his body, a practice which survived in parts of India into modern times.
Death is not always a great leveller, and husbands and wives, masters and servants, rich and poor, can often expect to continue in their earthly roles beyond the grave. In Finnish mythology, the virtuous dead are segregated according to a number of categories. Tuonela is a peaceful place for children and innocents, while Kyopelinvuori is for women who die as virgins. Then there's Surma, for those who died accidentally or in war, and Kalma, for those who died in sickness. Finally, Manala is a special hereafter for the common people, who are housed there in humble cottages.
At the opposite end of the scale from such rigid structures is the altogether more flexible doctrine of reincarnation, where nothing is final - at least not until the ultimate goal has been reached.
Belief in the transmigration of the souls of the dead into people and even animals is thought to have emerged in India almost 1,000 years before Christ. The cycle of rebirth, leading to eventual spiritual release, is central to the major Eastern religions, including Jainism, Buddhism and Hinduism. Its influence can be seen in some Ancient Greek writings, and it also made its way into Jewish mysticism (many Hasidic and ultra-Orthodox Jews still believe in reincarnation).
Hinduism has both heaven and hell, the former being a sweet-smelling, blissful place with the added advantage, according to one scriptural reference, of "countless celestial cars that move in the air", and the latter containing places "worse than those which are inhabited by animals and birds". Despite being housed in a fit new body equipped for the afterlife, the soul cannot remain in heaven or hell once its credit has run out or its debt has been paid, and it must return to Earth to continue the arduous journey towards perfection.
It is this state that the Buddha called Nirvanah, a Sanskrit word meaning "beyond all that can be described or defined". It is said to denote the extinguishing of a flame, and carries connotations of stilling, cooling and peace. At the time of the Buddha, a fire had to remain tethered to its fuel until it is blown out, at which point it is unbound, becoming diffused throughout the cosmos.
Today, around 500 million Buddhists around the world and some 45,000 in the UK are thought to pursue this vision of the afterlife - a view that, with its emphasis on personal transformation rather than worship, leaves little room for either heaven or hell.
Now almost completely vanished from popular culture, the "hell-mouth" or "hell's mouth" was once a familiar image across Europe.
Many, if not most, medieval parish churches once displayed wall paintings showing the Day of Judgment, and a common feature of these was the mouth of hell, into which flowed a stream of sinners.
In passion plays of the time, a physical representation of the hell-mouth was often a central feature. Smoke would often emerge from the jaws, and the structure would be large enough for the actors to pass through.
One artist's account from Chester notes that he was "paide for payntyng and makyng (A) new hell hed, 12 pence", and in 1557, a Coventry stagehand received fourpence "for keypyng of fyer at hell mothe".
In Britain, the reformation swept such diversions aside, and the wall paintings were covered up or destroyed, leaving the hell-mouth to fade from popular consciousness.