Hi !
The Andes offer quite a lot of features, with the rainbow mountains probably been one of the most photo friendly one. Here above is La Hornocal, or Cerro de 14 Colores (Mountain of 14 colours) which can be reached quite easily by car in Argentina and are best enjoyed around the sunset, from a Mirador at about 4200masl (provided you can bear the high altitude).
There are many other examples of these rainbow mountains, all formed though billions of years of tectonic movements and volcanic eruptions. Another testiment of nature true power, and also of the general randomness of things, as how many chances was there that these colours would mix so well.
Enjoy (or not) and stay tuned !