The Guiana Highlands are a very unusual mountain range covering parts of Venezuela, Brazil, Guyana, Suriname and French Guiana. The highlands are made of ancient sedimentary rock that is over two billion years old and are some of the oldest sedimentary rocks on the planet.
The flat-topped mountains are known as Tepuis (Pemón language) are considered to be sacred. Most of the peaks are surrounded by sheer cliffs of thousands of feet. Some of the mountains in this region are among the wettest places on earth and many of the world’s highest waterfalls spill of the mountains. The world’s highest waterfall, Angel Falls (979 meters/3212 feet high) spills off the top of Auyan Tepui. Other waterfalls among the world’s highest are (in order of height) Kukenan, King George VI, King Edward VIII, and Kaieteur. It is probable that many of the highest ones remain unreported.
Monte Roraima was the first of the Tepuis to be climbed and the credit goes to English botanist Everard Im Thurn on an expedition sponsored by the Royal Geographical Society in 1884. It was his subsequent lectures in England, that are believed to have inspired Sir Arthur Conan Doyle's book 'The Lost World'.
Some of the Guiana Highlands are extremely isolated, and many of the Tepuis have not seen any ascents. Most peaks require big wall experience and the sheer cliffs and inaccessible jungles surrounding the peaks make access very difficult or almost impossible. There are some exceptions, though. Monte Roraima is relatively accessible and fairly easy to climb. Auyan Tepui is beginning to see more ascents as is Pico da Neblina, Brazil’s highest mountain. All other mountains are very seldom climbed, if ever at all. Kukenan Tepui used to be climbable, but apparently is now closed. If you have any information on any of the other peaks, feel free to submit and addition/correction to this page.
Since the individual peaks in the Guiana Highlands have been isolated from each other for millions of years, many plants and animals have evolved in a different way on each mountain.
Many of the mountains are covered in permanent clouds and mist washing all the soil away, and leaving barren rock and water. Because of this many plants are carnivorous and feed on insects and small animals.
So far over 2,000 species of plants been found, and more than 50% are endemic to this region, meaning they are found only here, and many are only found on one peak. As of now, there are no introduced species known on any of the peaks, making this one of the only places in the world with no introduced species.
Some of the areas surrounding the peaks have a hot and dry climate, but the summits of the mountains themselve's must be some of the wettest places on earth.
In the western section of the Guiana Highlands, the "dry" season is December through March, but in the eastern sections of the highlands, this is unpredicatable and the weather changes too much from place to place to make generalizations, at least that's what I gather from looking at the weather charts for the region.