Like a lot of people, when a world leader passes away they're put on display so the living can pay their last respects. The only difference is, a leader's corpse is often displayed in a casket or glass case in a publicly accessible place, so their constituents and countrymen can all commiserate together.
Vladimir Lenin's body, for example, has been on display for more than 90 years. Even more insane than that? The former leader of the Soviet Union left behind a corpse that still looks as fresh as the day he died - fascinatingly preserved, lying in a mausoleum, with thousands of people visiting yearly.
The "Lenin Lab" scientists are those tasked with keeping the former leader's body in pristine condition. Though the former leader's body still looks as fresh as it did in 1924, over the years, over 200 scientists have replaced pieces of skin and lost eyelashes, smoothed out wrinkles, cleaned up mold, and even reconstructed much of the corpse's body to make up for the lack of fat layers under the skin.
A mixture of paraffin and other fillers is used to allow things like Lenin's nose or chin to be re-sculpted, creating the waxy and smooth look of his body today.
In 1941, as German forces moved across Europe, it was decided that Lenin's body would be removed from its resting place and moved to a secure location. Legend has it that then-leader Joseph Stalin even visited the corpse the evening before it left the Soviet Union.
The body traveled in a specially equipped train car to ensure it remained at the correct temperature, accompanied by a security detail and scientists trained to keep the body from decomposing.
After the Soviet Union was deemed safe enough in 1945, the Soviets undertook a mission called "Object No. 1" and moved Lenin's body back into its mausoleum.
Although the former Soviet Union is tight-lipped about the actual process for keeping Lenin looking so fresh and so clean, there is some information available from the scientists that maintain him.
The corpse is kept at a precise temperature in the mausoleum and resides within a display case that protects it from bacteria and other foreign bodies. Lenin is removed from his resting place every 18 months so that scientists can first clean and then embalm him again.
Pavel Fomenko, a former scientist that worked on the Lenin project, did tell the press in 2011 what the process was for embalming Kim Il-sung: "The body is then put in a tub of embalming liquid while maintaining specific temperature and humidity levels in the room, and the liquid thus replaces the water in the body." Alas, no one can know for sure if this is also the process for embalming Lenin.
Lenin's extended stay in the mausoleum in Red Square was not the original plan. The leader was set to be on display for the usual short span of time before being buried next to his mother in St. Petersburg, per his wishes. However, the Russian winter had different ideas, with temperatures of 19 degrees, it preserved the body by freezing it.
After 56 days of the perfectly preserved corpse remaining on display for droves of mourners, the Soviet Union received so much positive feedback from visitors that it decided to keep Lenin permanently maintained and on display. Thus began the great embalming experiment that continues to this day.