Other than just a desire to visit the renowned archeological site of Cuzco (the city as a whole), Casey needed to go there to organize logistics for the very difficult next leg of his journey.

Casey points out that the indigenous word 'Qosqo' means 'navel of the universe' or 'center of the universe', and that is how it was considered by the Incas. At 3400m (11,000ft) elevation, to them, it was the spiritual, political, and physical center of the universe.

In Cuzco, Casey is now only 30km (19mi) from the Apurimac tributary of the Amazon he had just been following. He is only 224km (139mi) from Mismi, the mountain where he will reach 'the source' of the Amazon.

Not long after Casey arrived in Cuzco he came down with Covid-like symptoms. This is even though he is double-vaccinated and even though he took painstaking precautions with mask-wearing and social distancing while minimizing any type of contact. He suffered for two weeks, self-isolating with fever and "coughing to the point of collapsing". He still is not clear whether it was Covid or severe flu. After 20 days, he feels he is past the worst of it thankfully except for a case of tinnitus he says he cures by listening to Hans Zimmer.

Before catching Covid, Casey did have a chance to visit Machu Picchu 80km (50mi) to the northwest of Cuzco. He had the fortunate occasion to be accompanied by a spiritual guide named Kucho. After Casey left, the nearby town of Aguas Calientes was beset by mudslides and floods trapping the inhabitants and requiring people to be airlifted out.