This talk discusses the use of (re)mapping and spatial modeling to create data-rich platforms for exploring urban histories and engaging scholars and the public. It highlights the application of geospatial technologies to extract data from various sources, build historical data models, and develop web-based dynamic map interfaces. The paper centers around the OpenWorld Atlanta (OWA) project, which aims to provide public access to historical information about Atlanta during the late 19th and early 20th centuries. OWA draws data from historical maps, city directories, archives, newspapers, and census data to facilitate spatially grounded research questions. Notably, the project focuses on Atlanta's transformative period in the 1920s, driven by population growth and infrastructure development, amidst the backdrop of racial discrimination under "Jim Crow" laws. OWA is built on open-source methods and philosophy, employing tools like Leaflet to pull spatial data and map overlays from Emory's Geoserver. Furthermore, the project utilizes Omeka, an open-source content management system, to manage digital content, including images, documents, and metadata. Metadata plays a crucial role in connecting geospatial features to records and digital objects. The platform incorporates many vector layers, including administrative boundaries, roads, rail lines, and buildings, allowing exploration based on specific years and themes. Usability and user experience studies are conducted to improve the platform's interface, user flow, and overall functionality, with a focus on accommodating diverse user groups. Overall, OWA serves as an example of how geospatial technologies and open-source methods can be used to create engaging platforms for exploring urban histories and fostering interdisciplinary collaboration between researchers and students.