The rain-sodden earth can hold no more water. It spills out across the mountainsides, creating a host of tiny streams. As they merge, the cargo of fertile soil driven downstream increases. Streams become rivers. Finally these rivers flow into the mountain bowl that is Lake Tana. The lake is filling up all the while, creating marshland on its shores. Here, weaver birds turn the flower heads of papyrus into building material and they set about constructing a woven city over the growing lake. Papyrus is one of the Niles great gifts. Growing along much of the river's length, it provides a strong waterproof building material for expert craftsmen such as these. The people of the Nile have also found it useful for building. The Ancient Egyptians even used it to make the paper on which they recorded the story of their great civilisation.


饱含雨水的大地容纳不了更多的水了。水涌下山坡，形成众多细小溪流。在它们汇流的同时，被冲至下游的肥沃土壤也随之增加。溪流汇聚成河流，最后注入山间的大碗——塔纳湖——之中。始终充盈着湖水的塔纳湖边出现了沼泽地。在这儿织布鸟将纸莎草的头状花序作为筑巢材料，打算在涨水期的湖面上建造出一座织布城。纸莎草是尼罗河的伟大恩赐之一。沿大部分河岸生长的纸莎草为织布鸟这样的手工艺专家提供了一种强韧的防水建材。尼罗河的子民也发现了纸莎草的这点妙处。古埃及人甚至还利用纸莎草制纸用以记录他们伟大文明的辉煌传奇。