Yellowstone National Park
Yellowstone National Park has one of the world's largest petrified forests, trees which were long ago buried by ash and soil and transformed from wood to mineral materials. This ash and other volcanic debris are believed to have come from the park area itself as the central part of Yellowstone is the massive caldera of a supervolcano. The park contains 290 waterfalls of at least , the highest being the Lower Falls of the Yellowstone River at .
Livingstone Falls
Livingstone Falls consist of a series of rapids dropping in . They start downstream Malebo Pool and end in Matadi in Bas-Congo. The Congo River has the second largest flow rate in the world after the Amazon, which has no falls or rapids (except near its sources). The lowest rapids of Livingstone Falls, therefore, are the world's largest waterfall in terms of flow rate — provided one accepts these rapids as being a waterfall. An interesting aspect of the long Livingstone Falls is the width of the channel. The channel is very narrow: in several stretches the channel width is less than 300 metres and for the majority of the length the channel is less than 800 metres wide. This is an extraordinarily narrow channel since the river flow rate typically exceeds .