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
Waterfall Country (Wales) now part of the unitary authority of Powys. A few miles further west are Henrhyd Falls on the Nant Llech, a tributary of the Tawe and to the southwest are Melin Court Falls on the Melin Court Brook, a tributary of the River Neath. These, along with Aberdulais Falls on the Dulais, a further tributary of the Neath are also encompassed by the term 'Waterfall/s Country' by some writers. Collectively the falls are one of the most popular natural attractions in South Wales, a fact which has brought about problems of erosion in the vicinity of many of the falls.