MummiesMummification is a form of preservation in which the body is dried out, thereby killing any bacteria which would destroy the flesh. The process can occur naturally, though it more often is part of a ritual for the dead, often with a flighty "afterlife" component. The Egyptians are most famous for the practice, though they weren't the only culture to make mummies, they just had the best P.R. The Inca and Aztec civilizations practiced mummification in some form. Once a popular way of commemorating the dead, mummification has been phased out in favor of embalming, a routine which takes a matter of hours, though the effect usually only lasts a couple of days.
In Egyptian mummification, the body is essentially disemboweled. All the soft tissue is removed, including the brains, which are sucked out through the nose. The organs are stored in individual Canopic jars, awaiting reassembly later. (The ancient Egyptians were not clear on the concept of organs.) The body was then stuffed with hydrous sodium carbonate, a desiccant salt. After forty to seventy days' drying, the body cavity has been completely sterilized. The salt is scraped out of the body cavity, which is oiled down, laden with frankincense, myrrh, and other spices, and then stuffed with sawdust and straw. The whole thing was wrapped in linen cloth and soaked in resin, for a total durability of several thousand years.