Bolivia is the most altitude-dominated country in the catalog. La Paz sits at 3,600 m, Titicaca at 3,812 m, the Uyuni salar at 3,656 m, and the Sud Lípez camps run to 4,900 m. Almost every itinerary here starts high and goes higher, so acclimatisation is the design constraint rather than a courtesy.
The Salar de Uyuni is 10,582 km² and works as two entirely different trips depending on water. The Cordillera Real runs about 125 km northeast of La Paz with more than a dozen peaks above 5,500 m, and Huayna Potosí at 6,088 m is real mountaineering however often it is described as the easiest 6,000er in the world. In the north, Madidi drops from above 5,000 m to 200 m of lowland Amazon inside one park, and Chalalán is owned outright by the Quechua-Tacana community of San José de Uchupiamonas.
Country-level constraints that decide whether a date is possible.