Along its 2700 kilometre route, the Zambezi River passes through hard rock in which it must excavate its bed and so forms rapids and waterfalls. Upstream from the Falls, a sudden southward bend causes the current to flow faster and more unevenly and eventually, the whole river – now 1700 metres wide – plunges into a chasm 108 metres deep which cuts right across its course. Isn’t it amazing that a river nearly two kilometres’ wide, becomes one of only a fraction of that width, in just a matter of seconds?

During the Jurassic age, volcanic activity caused molten lava to force its way up through fissures in the earth’s crust. This caused layers of gradually solidifying material which eventually became basalt rock, but with gaseous expansion in the lava, holes were formed which were comparatively susceptible to weather. There are now marked by bands of vegetation that grow in the loose rock along the sides of the gorges.

This solidification into basalt caused fissures which later widened after the volcanic activity had ceased. In Victoria Falls, these fissures run predominantly east-westerly, and in time, the river’s waters will flow closer to Cataract Island rather than the Eastern Cataract side, which is almost dry towards the end of the dry season. This will eventually break through to form a new gorge and broad fall along one of those east-west fissures already visible from the air.