Seconds, hours, weeks, months-none of these existed. The only units of time were those that people
could track with the naked eye. A day was make up of dawn, noon and dusk, which means there were no
"nine-to-five jobs" or "five o'clock shadows"!
The night sky marked the passage of time, and humans learned to track the moon through its phases.
As new moon followed new moon, the seasons changed, and as the seasons passed, the height of the
noon sun rose and fell.
Over 20,000 years ago, European hunters made an early effort at timekeeping. They scratched lines
and made holes in bones and sticks. Experts think these marks were made to record the phases of the
moon, from the new moon to the crescent moon to the full moon and back again. With this simple
beginning, the first calendar was born.