The Mummies' Museum of Guanajuato exhibits some real mummies whom were disinterred (taken out of grave) between 1865 and 1958, when the law required relatives to pay a tax in order to keep the bodies in the cemetery. If the relatives could not pay this tax, they would lose the right to the burial place, and the dead bodies were disinterred.
The mummified bodies were stored in a building out of sight, but in the 1900s the mummies gradually began attracting tourists and as a result, cemetery workers began charging people a few pesos to enter the building where bones and mummies were stored. Finally this place was turned into a museum called El Museo De Las Momias, The Mummies' Museum.
A law prohibiting the disinterring of more mummies was passed in 1958, but this museum still exhibits the original mummies. (Wikipedia)