With a land area of more than a million square kilometres, Bolivia is the fifth largest country in South America. The western part of the country is high and generally mountainous, with two Andean ranges running north to south. The Cordillera Real is the more easterly of these ranges and rises above the high plain of the 'altiplano' and above Lake Titicaca, at 3800 metres above sea level, the highest commercially navigable lake in the world. To the east extends the vast lowland area of the Amazon Basin, which includes half of Bolivia's total land area. With six 6000-metre peaks, the Cordillera Real is the country's most impressive mountain range and has one of the finest trekking routes in the whole of South America. From Sorata in the north, the rarely-undertaken trek along the spine of the range crosses several 5000 metre passes, visits isolated villages of the Inca-descended Quechua people and provides spectacular mountain views. Exploring the capital city La Paz, hiking on Lake Titicaca's Island of the Sun or climbing the 6000 metre peak of Huayna Potosi are other highlights of this charming Andean country.