Lucretius was a follower of the philosopher Epicurus, after whom the philosophical school of Epicureanism was named. He believed in atoms, and the heroes of Lucretius' poem were the atoms themselves. Neither Lucretius nor Epicurus believed in life after death.

There are poems and inscriptions which give evidence of them greeting the dead, whom some viewed as continuing their earthly existence in another place.

The Styx was the river which marked the boundary between Earth and the Underworld. It had significant power in Greek thought, and the gods swore by it, as mortals might swear by the king of the gods, Zeus.

The Vikings believed that dying in battle was the most glorious way to die. The reward for doing this, therefore, was to go to Valhalla and join the gods, feasting with Odin. This belief was shared in common with the early Anglo-Saxon warriors, prior to their conversion to Christianity. Dying from old age or cowardice was considered shameful.

In the Odyssey, Homer shows Odysseus going down to the Underworld, where he meets the ghosts of people who have died.

The Egyptians preserved the bodies of their dead pharaohs in a process called mummification. Many of their inner organs were taken out, and kept separately, whilst the main body was preserved. They were buried with things which they might need in an afterlife.

In Matthew's Gospel, Jesus is quoted as saying that it would be easier for a camel to pass through the eye of a needle, than for a rich man to enter the kingdom of heaven.

Pluto was a Greek name for the god of the underworld. Pluto was officially classified as a dwarf planet in 2006. Its name was originally proposed by an eleven-year-old schoolgirl from Oxford, who had a strong interest in Greek mythology.