Very few times, it is possible to see some integration similar to the one of the guide dog with its owner, since it becomes an extension of the latter. The dog is his/her eyes and its most certain connection to move around the outer world. The guide dog gives back autonomy to the blind person, so integrating him/her to the life. During training, dogs are taught to guide by avoiding obstacles. At the beginning, obstacles are very simple, and then they turn into real labyrinths, comprised by cars, poles, sidewalks, fences, etc. When the animal can overcome these obstacles with no difficulty, the instructor takes him to actual scenarios, first to the countryside and then to the urban traffic. A guide dog is one of the most complex specialties to achieve. They must be dogs capable of following their own criterion in case of adverse situations. It must remain alert and concentrated for hours, bearing warm weather, crowds, noises, distractions and many more things, since an error of the dog may be catastrophic.