The Nera River divides the small village of Ferentillo into two parts. The Precetto area, on the left bank of the river, is known for the Museum of the Mummies of Ferentillo. The museum's "macabre" title raises questions about the presence of mummies in southern Umbria. In fact, people in Precetto had a custom of burying their dead in underground chambers of the local church. This practice continued until the early 19th century when a decree during the Napoleonic era required the removal of bodies from the town. During this time, twenty-four bodies were exhumed that, unlike others, had preserved their organic features, such as hair, nails, and clothing. Some even showed signs of stab wounds and other injuries. The preservation of the Ferentillo mummies likely comes from studies suggesting that the unique chemical makeup of the soil in the crypt is rich in microorganisms and that there is good air circulation in the chambers.