When I think back on that ride I am reminded of another stage back in Peru. That was the stage to Cerro de Pasco which was also brutal. Cerro de Pasco was incredibly cold. As I recall one cyclist suffered from hypothermia. In the case of stage 66 it was the 35 km dirt/sand road which lead up what seemed to be a never ending ascent to a remote police station called Tocota. My speed was probably only around 7 km/h. The sandy conditions required considerable effort and attention to the track I chose. Apparently the police keep a check on illegal hunting of the guanaco which are similar to the vicuna.
Upon reaching Tocota I was badly dehydrated and totally exhausted. I was done. My mistake was pouring water from my bottle over my neck to cool down. What a prize.