Victoria Falls / Mosi-oa-Tunya

Victoria Falls, Mosi-oa-Tunya in the Tonga language — the smoke that thunders — were inscribed on the World Heritage List in 1989 as a transboundary property between Zimbabwe and Zambia. The Zimbabwean national park, declared in 1952, covers some 23 km².

The Zambezi plunges here through a fracture in the basalt plateau, forming a curtain of water more than a kilometre and a half wide and around a hundred metres high, reckoned the largest sheet of falling water in the world for its combination of width and height. The flow varies enormously between seasons, from a trickle in October to more than nine thousand cubic metres per second in April.

The geology explains the whole: the river has cut successively along the fractures in the basalt over hundreds of thousands of years, and the result is a series of zigzag gorges downstream, each of them an abandoned earlier waterfall. The cloud of spray that rises, visible for kilometres, sustains beside the rim a rainforest, permanently watered by that spray, that would not exist in an otherwise dry climate. The Taita falcon and the swifts of the falls nest on the gorge walls.