When did the following event happen?
Nelson Mandela becomes the first black head of state in South African history.
Select a space in the timeline below.
c. 3500 BCE
The wheel and axle are developed in Mesopotamia (present-day Iraq).
Note:
BCE means that the date is the number of years before the current era (CE/AD).
c. is short for 'circa' and indicates that the date is considered approximate.