They generally follow the coast of Brazil, then cross the Atlantic to the Cape Verdian Islands and the fly west of Africe, then entering the European continent over Spain.
Obviously, flights that originate in LIM
follow a different route.
For an excellent tool that will give you a (rough) estimate of how the route will look like see http://gc.kls2.com/
Please note this website does not map airways but great circle routes instead.