Lascaux caves in France hold prehistoric paintings from 15,000 years ago. Cro-Magnon created them during European ice age. Paintings include dots marking lunar phases. 13 dots and empty square show half moon cycle. 29 dots depict full 29-day lunar cycle. Curved dots indicate new moon disappearance. Patterns associate with bulls, antelope, horses, deer. Pleiades star cluster appears above bull's shoulder. German researcher Rappenglueck identified lunar calendar. Cro-Magnon tracked sun, moon, stars for timekeeping. Lunar calendars are oldest invented by mankind. Lascaux used as celestial calendar like Stonehenge. Survival depended on knowing natural rhythms. Paintings mix animals with geometric shapes. Access restricted to protect originals.