Early evidence of such practices appears as markings on bones and cave walls, which show that lunar cycles were being noted as early as 25,000 years ago; the first step towards recording the Moon’s influence upon tides and rivers, and towards organizing a communal calendar.[5] With the Neolithic agricultural revolution new needs were also met by increasing knowledge of constellations, whose appearances in the night-time sky change with the seasons, allowing the rising of particular star-groups to herald annual floods or seasonal activities.[6] By the 3rd millennium BC, widespread civilisations had developed sophisticated awareness of celestial cycles, and are believed to have consciously oriented their temples to create alignment with the heliacal risings of the stars.[7]