Because of the river gave them advantage to spread and conquer.
Step by step:
5. The Atacama Desert
6. Amazon River. Grande and Paranaiba River
7. Cape Horn and Diego Ramírez Islands.
8. Marajo, Falkland, Galapagos island. The Marajo is North-East of the mountain, Falkland is South-East, and Galapagos is North-West.
9. Through the Strait of Magellan into the Pacific Ocean; or around Cape Horn into the Pacific Ocean
10. Through the Caribbean Sea then through Panama Canal, next Southwest to the Galapagos. head south to Cape Horn, then go North-west through the Pacific Ocean to the Galapagos islands
