Colombia covers an area of 1,141,748 square kilometres delimited by Panamá on the northwest, by Venezuela and Brazil on the east and by Perú and Ecuador on the southwest¹ ,². The country has access to both the north Pacific Ocean as well as the Caribbean Ocean and is the natural bridge between South and North America³. Through the western half of the country, three Andean ranges run north and south. The western half of the country is a low jungle-covered plain, drained by spurs of the Amazon and Orinoco Rivers inhabited mostly by isolated tropical-forest Indian tribes. The fertile plateau and valley of the eastern range are the most densely populated parts of the country.