What city should I visit in South America?

t k asked: I am travelling to Santiago Chile and will have approximately 4 extra days and able to fly to another city in South America. What city would be the most interesting to visit for this short amount of time?

Which is the best city to visit in Colombia?

Mr. Senior asked: I am want to go to Colombia. Probably pick up their accent and stuff and I am wondering which city to visit. I am thinking of Barranquilla or Cali but is there any other cities that I would benefit more?