Located in the northwest of Bolivia, in the Cordillera Apolobamba, Chaupi Orco (which means "middle peak" in Quechua) is an impressive mountain range which stands over 6,000 metres above sea level. A quarter of it is located in Peru.
You can see the peaks of Chaupi Orco from the north shore of Lake Titicaca. Climbing the mountain is only for experienced mountaineers who are in excellent physical condition, and you have to climb from the Bolivian side as it's considered more easily accessible. It takes a week to trek from the village of Pelechuco, located 3,000 metres above sea level, and you'll typically start with an acclimatisation walk which will allow you to explore this exceptional place.
Please be aware that you must only climb this mountain with a professional guide and you'll also need a strong resistance to altitude.