5. Mount Roraima, Guyana/Brazil/Venezuela This massive sandstone plateau stretches across the borders of Venezuela, Brazil and Guyana. The impressive plateau is surrounded on all sides by 1300-ft. cliffs, creating an isolated and unique ecosystem. At the top are amazing rock formations have been carved by wind and water, and there are crystal beds that contain large, crystal formations. Stunning views from the top over the Gran Sabana of Venezuela, provides the best cloud cover lifts. At the moment, visitors can only approach from the Venezuelan side, and the Paratepui Route is the easiest for non-technical climbers.