They are accidental modern mummies and were literally "dug up" between the years 1865 and 1958 when a local law required relatives to pay a kind of grave tax. You could pay the tax once (170 pesos) and be done with it; this option may have appealed to wealthier individuals. But you were also allowed to pay a yearly fee (50 pesos); this would have appealed to less wealthy families. However, if the relatives could not pay this yearly tax for three years, the body (which had, by the way, become accidentally mummified) was dug up from the cemetery and (if the fee still wasn't paid) placed on display in El museo de las momias.





Above right: This museum is known to have the smallest mummy in the world, a fetus from a pregnant woman who fell victim to cholera.

The Guanajuato mummies are some of the strangest ones ever placed on display. Some of the mummies are displayed standing up.Some are clothed, some aren't. A few are wearing only their socks and/or shoes. Some are old, others are only infants. One tiny baby mummy is labeled, "La momia más pequeño del mundo"--the smallest mummy in the world. The baby and the mother (they died during a caesarean section) are in the museum, but they will not be found together.





Above left: In some cases due to trying to control the spread of cholera, the dying were buried alive by accident. As a result, some of the mummies have horrific expressions attesting to their death in the tombs, though most expressions became fixed postmortem. Above right: The remains of a Dr. Remigio Leroy, , perfectly preserved by the dry conditions. Many of the mummies still have their hair, teeth and nails.

The museum contains a few local legends as well. For example, one body was said to belong to a woman who had been buried alive called Ignacia Aguilar. When the Mummy Road Show hosts researched the mummy, they concluded that two factors suggested this legend was correct: the woman's arms were raised over her face and her forehead had scratch marks.



Above: Ignacia Aguilar was suspected to have been buried alive.

These mummies are pretty creepy, all the more disturbing considering they are really very recent.

Sources:

http://www.mummytombs.com/mummylocator/ ... ajuato.htm
http://en.wikipedia.org/wiki/Mummies_of_Guanajuato
http://accidentalmummies.com/about-the-exhibit.php