Archaeologists have recently discovered what they believe it's the world's oldest calendar in an Aberdeenshire field, in Scotland. It consists in 12 pits which appear to mimic the phases of the moon and, therefore, tracking lunar months. They also align on the Midwinter sunrise, providing an annual "astronomic correction" in order to better follow the passage of time and changing seasons. The scientists believe it was created about 10,000 years ago (in the Mesolithic Period) by hunters-gatherers, making it thousands of years older than time-measuring monuments in Mesopotamia, previously known by archaeologists as the oldests calendars.
~Ally