It is amazing what kind of vegetation you can find around the world. Near Porto was an amazing botanical garden that featured a full garden of cactus. While cactus is best known for growing in a arid and dry environment, Porto is home to some moisture, especially being so close to the ocean. This was obviously not a natural vegetation to the area, but it was interesting to see how the cactus flourished. Walking around the gardens gave you the feel that you were actually in the South Western US, as opposed to northern Portugal. Worth walking through if you have the time.