Quinn:
Wolfram's Entity Framework is a vast knowledge-base that provides us with computable data on a wide range of topics. However, it does not turn lat/longs into GeoPoints, which is what you need.
Try this out (I also added some missing commas between options):
positions =
Map[GeoPosition, {{-15.707663, -47.911551}, {-25.363882, \
-57.717899}, {-34.921971, -56.046862}}];
GeoGraphics[{GeoPath[positions], Red, Point /@ positions},
GeoRange -> "World", GeoCenter -> 40,
GeoBackground -> "StreetMapNoLabels"]
So, check out GeoPosition[], used above.
Have a great and safe holiday.