Penal is one of the archeological sites located in the Sierra de Atapuerca (in Spain).
This particular site is a small cave located in front of the Gran Dolina (this cave was actually part of the same system as the Gran Dolina, but they are independent channels now). The two caves have a wildly different sedimentary record.
This is the only one of the Sierra de Atapuerca sites that shows no signs of human activity. This cave seems to have mainly served as a home to birds of prey and small mammalian carnivores. However, the taphonomical and sedimentary data from this cave has has proved to be very valuable in interpreting the ecology of the area.
Sources
http://romani.iua.urv.es/webEN/Atapuerca1EN.html
http://www.med.abaco-mac.it/issue001/articles/arkeos/garcia.htm
http://www.atapuerca.com/eng/around.htm