This seminar report summarizes augmented reality (AR), which combines real and virtual worlds. It discusses the history of AR beginning in 1966, and describes the key components of an AR system including head-mounted displays, tracking systems, and mobile computing power. Applications of AR discussed include education, military, sports/entertainment, and medicine. Advantages include interactivity and personalization, while disadvantages include physical danger and privacy issues. The report concludes that AR will continue to blur real and virtual worlds and have applications in many fields.