Intramuros is a Fortified City in Manila built during the Spanish colonial era in the Philippines. It can be accessed through different puertas or gates strategically located on the surrounding walls protected by baluartes and revellins. These gates can be categorized into two—the old and original gates and the current gates that were created during World War II to provide access to the military tanks in and out of the city. However, there was one gate that can only be seen on the old maps and archival records, but no remaining physical records can be found—the Puerta al Quartel de Banderas. This study is aimed at finding the original location of this lost Puerta al Quartel de Banderas and assess its cultural significance following the format and criteria set by the Burra Charter of 2013—ICOMOS Australia and guidelines produced by the Department of Environment and Heritage Protection for Queensland Heritage Places. Desk research was made to gather information regarding the historical context and physical description of Puerta al Quartel de Banderas and its built environment. Site visits, actual inspections, and investigations were conducted to document its physical fabric, oral histories, and values from the community, as well as the Intramuros Administration (IA). All information gathered was then validated, and survey results were tabulated and assessed, leading to the formulation of the Statement of Significance. In conclusion, lost, missing, destroyed, demolished, and built heritage assets that are just waiting to be rediscovered, such as the Puerta al Quartel de Banderas in Intramuros, Manila, present unique challenges and opportunities for heritage conservation strategies and further research. The interpretation and presentation of lost and forgotten heritage plays a crucial role in shaping the narrative for future generations. When historical sites are no longer physically present, interpretation and presentation become powerful tools for keeping the memory alive and conveying its significance to the current and future generations, therefore forming new collective memories.