There’s an incredible story about Orellana, who captained the first journey down the Amazon River in the 1500’s with Gaspar de Carvajal taking notes. They described cities of hundreds of thousands of people, and sailing for days going through city after city.

Decades later people tried to repeat the journey and didn’t find major cities, ultimately calling Carvajal a liar. The reality was everyone died due to new diseases. It’s hard to imagine the impact disease had on South America in particular