Emotion is a fundamental component of being human. In human daily social life, knowing the emotional feeling of a person is intuitive but for a computer emotion recognition is harder. Emotion could be expressed through many social behaviours, including voice, gesture, psychological signals, etc., but the main part of the overall impression is the facial expression. FER (Facial Expression Recognition) deals with the automatic analysis of facial behaviours to recognize emotional states and, during the last decade, it found application in several fields, as human-computer interaction (HCI), virtual reality, advanced driver assistant systems (ADASs) and entertainment. Although interest in automatic facial expression recognition has been increasing and many resources are invested, FER still presents many challenges to tackle, one of these are databases.