Kinshasa, Congo
The Congo is a massive river, but huge rapids downstream of Kinshasa mean that it's not navigable from the sea. The volume of water and the drop are such that a hydro plant would be able to supply most of sub Saharan Africa, but as you may have guessed, it's a work in progress - and one which hasn't really got far off the drawing board.
Tomorrow we have another 0500 start - for the flight to Kisangani. The plane we were due to take has been commandeered by some ...