Except the buildings made of solid stone blocks, dirt blocks are used in Cuzco. Dirt, straw and water are the only ingredients. The walls all have roofs to preserve the blocks. Without protection, they will last 5 years, I´m told.

Next to the control station at the entrance to Cuzco. Later I will find out what the survival issue is when I begin trekking the Andes

The landscape from the highway is impressive with farms on the slopes. My friend told me that it is much like Switzerland. Trees are small and rare. The locals don't heat and cook on propane. With no fires and few diesel vehicles there is no smog in the valley.