Restoration is a process that converts an existing building either into its former position or an improved form It is mainly carried out on historical monuments. It protects the buildings from serious damage by replacing materials and techniques with new ones ex: installing climate controls. Preservation, rehabilitation, and reconstruction are the three main levels of restoration. To become a professional restoration architect one must possess a thorough knowledge of architectural theory, structural engineering, and design. He must also be proficient in computer-aided designs.