I'm currently reading "Across South America" by Hiram Bingham III (published in 1911). It's the first hand account of Bingham's first trip across South America.

He visited most of the eastern seaboard of south america (which is basically the Brazilian coast) by boat, and eventually landed on Argentina, whence he travelled overland across the Andes through Bolivia and Peru, finally arriving in Chile (where he represented the US as a delegate in the first Pan American convention).

It's a FANTASTIC account of the economic, social and political situation of most South American countries. Intelligent, and brutally honest. This trip would plant the seeds of Bingham's love for exploration and for Peru's pre Columbian civilizations (which would culminate with him discovering the last Inca lost city: Macchu Pichu).

Before that I read Inca Land, also by Hiram Bingham III, which is about his later exploration trips (from 1911 to 1916) where he identified the sites of several Neo-Inca cities that had been talked about in the Spanish chronicles of the XVIth Century (but the locations' true identities had been forgotten over time). He also misidentified a few sites (hey, nobody's perfect). But most importantly he discovered the best preserved city of the Neo-Inca empire which at that point was basically forgotten and unknown, even to the people that lived in the area (due to the INSANE geography of the region).