Interaction with other human beings had been limited for the past eight days. We were going south on isolated roads alongside the chilean/bolivian border. We  passed few trucks carrying their heavy loads, blowing huge clouds of black smoke and some of their drivers raising their hands to greet us. We bought coca leaves from an old woman selling goods on the plazas of otherwise lifeless pueblos high in the Andes. And we handed worn bills to men selling fuel from big blue barrels in the backyards of their small houses. Only few words were exchanged. The Altiplano is a quiet place.