What to visit in South America? What are the most beautiful colonial cities to visit? Certainly the most interesting country to visit in South America is Peru, with the wonderful Machu Picchu and Cuzco at the forefront. The pre-Columbian legacy and that left by the Spanish colonizers is unimaginably charming. In Brazil, you will visit several towns with colonial architecture typical of the Portuguese. Many believe that they were the sternest of all European colonizers. When visiting the divine Buenos Aires, you will feel like you are in Europe. The city is very much inspired by Rome, Madrid and Paris. The real pearl in the north of the continent is Cartagena in Colombia. It's a fantastic place to go from hell to sightseeing. Great beaches, majestic city walls.