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A team led by a Tanzanian archaeologist has challenged long-held beliefs that Swahili coast civilisation was heavily influenced by outsiders who arrived to trade with the local communities in East Africa.

After excavating an extensive cave on the island of Zanzibar, Felix A Chami, a Dar es Salaam University professor, discovered evidence of settlements, animal domestication and trade dating back to more than 3,000 BC.

The BBC's Hassan Mhelela has visited the cave and sent this report for the Focus on Africa programme on BBC World News TV.

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