Ghana long ago dammed the River Volta, Egypt the Nile, Zambia, Zimbabwe and Mozambique the Zambezi.

ECONOMIST: Dams in Africa

For example, significant cooling and strong dynamical effects after the Laki event and other high-latitude eruptions are believed to have caused decreased flow of the Nile River in Egypt and weakened African and Asian monsoons based on climate model simulations, with potentially very significant impacts on food and water supplies.

CNN: How volcanoes can change the world

Balloon rides are a popular way to see the numerous ancient sites which line the banks of the River Nile at Luxor, in the south of Egypt, such as the temple of Karnak and the royal tombs in the Valley of the Kings.

BBC: Egypt hot air balloon tragedy: Tributes paid to victims