The Grand Inga Project is now available. I can’t say I intend to buy it, but the trailers and snippets are worth watching.
And the article in Kayak Session is worth reading (for free, right now). Very impressive photography.
Most of the world’s big “unexplored” places are isolated by both harsh conditions and distance, which makes it intriguing that the world’s biggest (1,500,000 cfs!) rapids are close to one of the world’s largest cities. A good reminder that vision, rather than any external factors, is the largest limitation on adventure.
Bedrock & Paradox 
– [I]ntriguing that the world’s biggest (1,500,000 cfs!) rapids are close to one of the world’s largest cities. –
In the Congo the river is the road! The anastomosing rivers which sometimes show up on the very earliest European maps of North America seem to be based upon misreadings of the typical American Indian cartographic practice of representing travel networks as a whole without distinguishing between land and water routes.
http://www.npr.org/2011/06/01/129176374/river-of-life-congo-odyssey?jump=0