The search for the source of the Nile was one of the major events in Victorian African history. Whether it was Burton, Speke, Livingstone or Stanley - they were all obsessed by it at some stage or other and until now I have never understood why it took them so long to figure it out.
Herbert (our driver) told us the other day that the source was Lake Victoria, but I recall driving past the "Source du Nile" hotel in Burundi many years ago and wondered which was correct.
The answer to this puzzle is not straightforward (which helps to explain the Victorian confusion).
In simple terms, if you travel up the Nile from Egypt and into Sudan you come to the first major confluence at Omdurman, which is that of the Blue Nile (flowing west from Lake Tana in the Ethiopian highlands) and the White Nile, flowing north from Uganda.
We now know that the latter is the longer of the two, but once you get into Uganda there is another major confluence - of the Albert Nile (flowing north east out of Lake Albert, which is bisected by the DRC/Uganda boundary) and the Victoria Nile (flowing north west out of Lake Victoria, which is divided between Uganda, Kenya and Tanzania). The two lakes obviously draw on different catchments and determining which of the rivers feeding into these lakes was the longest was at the heart of the Victorian debate.
Lake Albert is fed by a catchment area running south down the rift valley to the west of the Rwenzori Mountains (by the Semiliki River, which emerges from Lake Edward to the south and then by both Lake George and Lake Bunyonyi -in southern Uganda - which both feed into Lake Edward).
However, it is the headwaters of the catchment rivers to the east feeding into Lake Victoria which are the longer.
The Kagera river (which Speke crossed and named in what is now Tanzania, but didnt bother to trace back) has its headwaters in Rwanda and Burundi and then runs east into Lake Victoria. However, a BBC team which ascended the river from the Nile delta to the source have claimed that the longest of the Kagera tributaries has its source in the mountains of Rwanda and not in the mountains of south east Burundi - as was previously thought to be the case.