The Diplomatic Quarter plays a unique role in metropolitan Riyadh as it accommodates the ambassadorial community which lends it a distinct profile with an inter­national and political significance. Its very political nature is made evident by the high level of security that has been introduced since the early 1990s. As a result of the enhanced security environment, and due to its setting and access layout, the actual development has deviated substantially from the original plan. Although of highest urban, architectural and landscape quality, the Quarter has grown into the kind of enclave, which the planners originally saw as the very antithesis of their plan. As a response to these developments, the High Executive Committee for the Development of Arriyadh called upon the original authors to review the Master Plan and identify appropriate development options for the next twenty years. The comprehensive review was to examine issues such as integrating security measures in the urban design, enhancing the design of the central core, alleviating traffic problems, promoting building activity and redefining land uses for vacant lots. Key elements consisted of allocating space for embassies of nations which did not exist 20 years ago; introducing innovative model solutions towards optimizing visitor flows the embassies and depicting the modifications in preliminary zoning proposals. In an interdisciplinary process all proposals were compiled into an updated Master Plan providing a development guideline for the next 20 years.