I visited S. America last year for 3 1/2 months. Peru, Chile, Argentina, Uruguay. British Airways is a transfer partner of UR. BA is a partner with LAN. I was able to get many many flights using BA miles on LAN. 4500 miles each way if the flight is under 650 miles. Lima - Cusco, Lima - Tacna, Lima - Iquitos. San Pedro de Atacama to - Santiago, Mendoza - Buenos Aires. Buenos Aires to Iguazu. You need to have lots of flexibility, but it worked great for me.