They call her ‘Sleeping Beauty,’ the world’s most beautiful mummy. Rosalia Lombardo died from pneumonia in 1920 at the tender age of 2. Her body was embalmed by Alfredo Salafia (below), put into a glass coffin, and placed inside the Capuchin Catacombs in Palermo, Italy. If it were not for the oxidizing amulet of the Virgin Mary resting atop her blanket, you would swear she had died a few days ago.

Very little is known about Rosalia’s life, and, until recently, even less was known about Salafia’s preservation methods.

Embalming as a means of memorializing the dead has ancient roots, dating all the way back to the Egyptians beginning in 3200 BC. During this period, embalmers removed the internal organs before rinsing the empty cavity with palm wine and filling it with natron salts. Over the next 40 days, the body would begin to dry out and mummify. The internal organs—which were washed, coated with resin and wrapped in linen strips upon removal—were either placed back into the body’s cavity at the end of this process, or stored in canopic jars.

This method is very different from the one used today, in which preserving fluids are pumped through the corpse’s vascular system. The end result is very different as well. Instead of a dried-out mummy that bears little resemblance to the living, you get a corpse that looks more or less as if it is sleeping. Vascular embalming became popular in the mid-19th century, and was largely driven by the sentimental desire to return the bodies of dead soldiers to their hometowns for burial during the American Civil War.

Embalming techniques varied greatly in the late-19th and early-20th centuries. For many years, Salafia’s formula remained a mystery. That was until Dario Piombino-Mascali at the Institute of Mummies and the Iceman in Bolzano tracked down Salafia’s living relatives who had in their possession a number of the embalmer’s handwritten papers. In his notes, Salafia revealed that he injected little Rosalia with a mixture of formalin, zinc salts, alcohol, salicylic acid and glycerin. It was the latter which prevented the little girl’s body from drying out too much. It was the zinc salts which gave her corpse its rigidity and stopped her cheeks and nasal cavity from caving in.

Nearly 100 years after her death, Rosalia looks unnervingly alive. In 2009, an MRI of Rosalia’s corpse produced the first 3D image of the little girl and revealed that all her organs were perfectly intact. Moreover, in time-lapse photos, Rosalia’s eyes open and shut, showing her blue irises to be nearly undamaged by decomposition (video below). The eyelid movement is most likely caused by changes in room temperature and humidity down in the catacombs, yet it has fueled many cult beliefs that Rosalia’s spirit returns to the body.

Little “Sleeping Beauty” draws thousands of people to the Capuchin Catacombs each year. Visitors armed with cameras and iPhones each vie to get a shot of her lying in her glass coffin. But for me, Rosalia is an unsettling sight. She is a reminder of the dangers of childhood in a pre-penicillin era, and represents her family’s unwillingness to let go of her even in death.

In her defiance to decay, Rosalia Lombardo has become Death’s doll, an eternal playmate that can neither age nor disappear.