Ausangate Circuit
In the book description of this trek, it reads that you get pretty much everything on this trek - from seeing indigenous villages, alpaca herds, snowy mountain ranges, vicuňas (wild alpaca-llama ancestors), hot springs, and hiking 80km at 3500m or higher. They did not lie. This was one of the better treks that I have been on (and, as my faithful readers know, I have been on some good treks this year).