I successfully made it to the Source of the Nile!
Well, OK, there are many sources of the Nile, but the people of Burundi confidently assert that their Source du Nil spring is the southernmost source that eventually flows into the Nile. And, just to remove any doubt, it comes complete with an actual pyramid. Ha!
The spring itself now emerges from a small pipe a little below the monument, before starting a very long journey North.
Separately, back in Bujumbura, I successfully discovered the spot where the explorer Stanley successfully discovered Dr Livingstone.