acid or a solution of lye, followed by disposal as liquid. A specific method is alkaline hydrolysis (also called Resomation). Advocates claim the process is more environmentally friendly than both cremation and burial, due to emissions and embalming fluids respectively. On the other hand, many find the idea of being "poured down the drain" to be undignified. Other less common Donation for study – donation to a medical school or similar – after embalming and several years of study and dissection the body is usually eventually cremated. Space burial In cases of war, genocide, or natural disasters including disease epidemics, large groups of people have been buried in mass graves or plague pits. A body farm involves a similar method of disposal as an object of scientific study. In some traditions, for example that practiced by the Spanish royal family, the soft tissues are permitted to rot over a period of decades, after which the bones are entombed. Diamond synthesis, in which the remains of a body are converted into diamonds. Means of preservation In some cases an attempt is made to preserve some or all of a body. These methods include: Cryopreservation Mummification; the most well-known examples are from ancient Egypt Taxidermy; an extremely rare form of preserving a human body. Famous historical examples include an African tribesman, and sideshow performer Julia Pastrana. Plastination: The preserved (embalmed) body is prepared by dissection or slicing and fluids are replaced with inert plastic for anatomical study by medical students or display in museums. This technique was pioneered by Gunther von Hagens of the Institute for Plastination. Human remains of archaeological or medical interest are often kept in museums and private collections. This practice is controversial (See NAGPRA). In the cases of Native Americans in the United States, possession of remains and related objects is regulated by the NAGPRA Act of 1990. Preparation for disposal Different religions and cultures have various funeral rites that accompany the disposal of a body. Some require that all parts of the body are buried together. If an autopsy has occurred, removed parts of the body are sewn back into the body so that they may be buried with the rest of the corpse. When it is not possible for a body to be disposed of promptly, it is generally stored at a morgue. Where this is not possible, such as on a battlefield, body bags are