“Nile is the longest river in Africa! Or maybe, in the world!” Children are innately curious. So, learning fascinating facts about the Sanaga, Nile, Niger, Limpopo, Zambezi, and Congo in the second-largest continent on the planet will surely quench their curiosity. And this can quickly turn into a more engaging game when paired with the interactive crossword puzzle online on names of rivers in Africa – Sanaga, Nile, Niger, Limpopo, Zambezi, Congo. The children will surely learn interesting facts as they complete the puzzle.. 2nd, 3rd, 4th, 5th, 6th, grade social studies game.