I would say the Andes highlands due to its relative inaccessibility being a very mountainous area. When I travelled in Latin America in 1969-1970 we went by bus south of Popayan in southern Colombia on a very narrow cobbled road with drop offs of 1000's of feet and very slow progress so I imagine this would be a similar situation in the Venezuelan Andes ie poor road access and perhaps poorly inhabited. On the other hand, in Peru the Andes has ancient Inca fields ie terraced fields on it so was partly accessible even in the 1500's/