Guyana the dryer savannah areas in the south-west; and the smallest interior lowlands (interior savannah) consisting mostly of mountains that gradually rise to the Brazilian border. Some of Guyana's highest mountains are Mount Ayanganna (), Monte Caburaí () and Mount Roraima ( – the highest mountain in Guyana) on the Brazil-Guyana-Venezuela tripoint border, part of the Pakaraima range. Mount Roraima and Guyana's table-top mountains (tepuis) are said to have been the inspiration for Sir Arthur Conan Doyle's 1912 novel "The Lost World". There are also many volcanic escarpments and waterfalls, including Kaieteur Falls which is believed to be the largest water
Kaieteur Falls combination of height and water volume, and Kaieteur is among the most powerful waterfalls in the world with an average flow rate of 663 cubic metres per second (23,400 cubic feet per second). Kaieteur Falls is about four times higher than Niagara Falls, on the border between Canada and the United States, and about twice the height of Victoria Falls, on the border of Zambia and Zimbabwe in Africa. It is a single drop waterfall. Upriver from the falls, the Potaro Plateau stretches out to the distant escarpment of the Pakaraima Mountains. The Potaro River empties into the Essequibo River