ancient egyptian mummies existed for thousands of years intact. so how did ancient egyptians mummify when at that time it was extremely difficult to prevent decomposing corpses?
choosing to donate the body to science can ensure a person can still contribute to society even after death. the bodies of donors will be preserved for use in anatomical studies
to be able to self-mummify, japanese monks in ancient times underwent harsh cultivation and eating regimes that lasted for a decade. they consider it a form of enlightenment.