Sunset in the Victoria Falls. Victoria Falls is the result of soft sandstone that fills huge cracks in the hard basalt rock of the plateau. As the Upper Zambezi flowed across the plateau in ancient times, it found the cracks and started wearing away the softer rock, eventually creating a series of gorges. Geologists estimate that the river has been falling into these gorges for at least the last 100,000 years. As the rock wears away, the cataract follows these gigantic cracks and moves further upriver across the plateau. Dr. David Livingstone had been traveling down the Zambezi River in Southern Africa for several months. Perhaps a hundred miles upriver during this expedition he had come to Ngonye Falls. Livingstone had found the cataract very impressive. The falls were only about 60 feet high but extended over the whole length of the wide river and the amount of water that rushed over them was staggering. However, on this day, November 17th, 1855, he been told he would be seeing a spectacular cataract that would dwarf the one at Ngonye. Livingstone, like most Europeans, had some doubts about this. After all, at this point the river was flowing sluggishly across a flat plateau without a mountain or valley in sight. How could you have a big waterfall without a land feature that would cause a sudden change in the height of the river? As the canoe they were paddling in headed downstream, however, Livingstone began to hear a distant rumble. Ahead a plume of mist arose from seemingly nowhere. By the time the canoe was pulled up on a small island and Livingstone had walked to the edge of the cataract, the sound had become a deafening roar.