I left 2 weeks ago Buenos Aires to go to the waterfalls of Iguazu: these are purely amazing! It is hard to describe with words but have a look on my pictures, it can give you an idea of the beauty ...
I stayed 1 day in El Calafate to see the gorgeous glaciar Perito Moreno (see pics), large of 5 km, long of 30km and high up to 60m! And good news, it is one of the unique glaciars in the world ...