They are sanitization, presentation and preservation (or restoration) of a corpse to achieve this effect.
It has been practiced in many cultures. In classical antiquity, perhaps the ancient culture that had developed embalming to the greatest extent was that of Egypt, which developed the process of mummification. The Ancient Egyptians believed that preservation of the mummy empowered the soul after death, the latter of which would return to the preserved corpse. Embalming in Europe has become much more common in the more industrialized regions. Arterial embalming is believed to have been first practiced in the Netherlands in the 17th century by Frederik Ruysch.