Mexico is a hot spot for alien activity and extraterrestrials have been a part of their culture for many years. This is why it is less of a surprise to hear that 13 otherworldly skulls were discovered in Mexico in 1999. The bones discovered are believed to be about 1000 years old. The skulls were discovered when crews were digging an irrigation ditch in the Sonora Desert in northwestern Mexico. The ancient cemetery was home to 25 skulls total. Of those 25, 12 were human and 13 had a very distinct alien feel to them. Recently, analysis of the remains revealed something very interesting about the skulls.