Study of time measurement in different cultures including the Maya civilization with their long count calendar, complex astronomical sciences, precise calculation of Venus cycles, recording of stelas in Tikal and Palenque. Ancient Egypt's 12-hour day/night system, 36-star group decans, sun dials, water clocks, and the use of base-10 numbering system. Hieroglyphs for recording events and festivals such as Akhet - inundation season