WLA Studio is currently working with the National Park Service (NPS) to prepare Additional Documentation for the National Register of Historic Places Nomination for the San Juan National Historic Site (SAJU) in San Juan, Puerto Rico. SAJU includes the historic Spanish fortifications of Castillo San Felipe del Morro, Castillo San Cristóbal, Fort San Juan de la Cruz (El Cañuelo), and most of the historic wall surrounding Old San Juan, Puerto Rico. The fortifications are the oldest of European design in the United States and exemplify the evolution of military architecture and engineering over five centuries. Today, SAJU contains several historic buildings and structures that were essential to the mission of Fort Brooke, a main United States Army post in the Caribbean during WWII. As a part of this project, WLA Studio provided NPS with additional information regarding historic resources the United States War Department constructed and utilized between 1939 and 1945, during preparations for and active involvement in the Second World War (WWII). The purpose of this Additional Documentation is to provide historic context to these resources, evaluate their significance, and evaluate their integrity.