Criterion (iii): The Landmarks of the Ancient Kingdom of Saba, with the monumental architecture and the preserved hydraulic structures erected by the Sabaeans, demonstrate high level of technological know-how and engineering skills. Criterion (iv): The Landmarks of the Ancient Kingdom of Saba with their monumental architecture and diverse technological advances represent an outstanding example of an ensemble that testifies to the cultural tradition of the Kingdom of Saba that served as a central node in the frankincense trade route through the Arabian Peninsula. AuthenticityThe authenticity of the individual component parts and of the whole series can be considered as highly vulnerable due to historical developments and contemporary threats. Besides the legal-institutional protection, the component parts benefit from traditional protection provided by the local tribes. Conservation and Management Guidelines have been developed to guide future management and protection of the component parts.