4,000 Years Ago in West Africa

The Sahara desert continues to grow, pushing the borderland of the savanna (called the Sahel) further south. The pressure on the herdsmen of the Sahel to move south as pasture lands disappear also continues to increase. Overuse of pasture land, stripping away all plant cover allowing the soil to dry out completely, may have added to the problem of a climate that was already becoming drier. This process of desertification continues to this day.

Numerous megaliths or standing stones exist in the area around Bouar in what is now the Central African Republic, sometimes called the African Stonehenge. Possibly built as tombs, similar to the stone tombs found in Europe, little is known about these ancient monuments. Usually the stones are set up in groups and were placed near river sources or at the entrances of valleys. The huge stones are typically 1.5 to 2 metres high, but some are up to 5 metres tall and weigh 4 tons. In the native language, these monuments are called tajunu.