Which is the only team that won multiple super bowls without having lost any?

Baltimore Ravens which is based on Baltimore, Maryland is the only team that won multiple super bowls without having lost any. The Ravens have been one of the more successful franchises since their inception, having qualified for the NFL playoffs ten times since 2000, with two Super Bowl victories, two AFC Championship titles, 15 playoff victories, four AFC Championship game appearances and are currently the only team in the NFL to hold a perfect record in multiple Super Bowl and Thanksgiving Day appearances.