There are many sights in the city center, the most interesting to me was the Basílica de Nuestra Señora del Pilar. It is known for its four mighty bell towers, which you can see from anywhere in the city. Personally, I was most impressed by the altar with its grandeur and the details themselves.
We also visited the so-called largest freshwater aquarium. Considering that it is supposed to be the biggest, I was not really surprised, the building itself does not look anything special, we paid as much as 15 euros per person for the entrance fee. It could be seen in the aquarium itself that it is already older, so it seems to me that it needs renovation. In addition to the aquarium, there is also a small zoo, which did not surprise me. It seems to me that the most interesting part of the aquarium was the last point, it was an otter, which was very active, we observed it for about 10 minutes. Personally, it seems to me that the whole thing was not even worth about 15 euros.