On the first day the bus took a route that peaked at 4910m. The bus pulled over so we could get out and wander around. I certainly felt "spacey". The day finished at 3,640m in a town named Coporaque. By dinner time I had a headache but fortunately it went away after 24 hours.
Some struggled with altitude for the next few weeks. This included headaches, flu-like symptoms, cramps or diarrhoea. The Machu Picchu trek goes up to 4200m, so being acclimatised to altitude is important.
On the second day the bus re-traced its steps to Colca Canyon. The canyon is twice as deep as the Grand Canyon and there are huge condors to be seen.
We follow the road all the way back to Arequipa, for a second stay.