The purpose of this district is to protect unique areas in the City of Maumee by defining architectural standards and design review mechanism. Unless specifically modified by the overlay zone the requirements of the underlying zoning district are maintained along with the additional requirements of the overlay zone. Overlay districts allow modifications and impose further restrictions to maintain the character and/or architectural integrity of important sites, districts, or structures within the City. This section also establishes the procedures by which sites and structures within the overlay zone shall be reviewed.