The simmering conflict between Egypt and Ethiopia over the construction of a massive dam could have grave ramifications.

The Blue Nile is one of the river’s two principal tributaries that converge near the Sudanese capital Khartoum and then flow northwards through Egypt to the Mediterranean Sea. As the world’s longest river system, the Nile functions as a lifeline to the 11 countries it traverses, supplying them with both water and hydroelectricity.