This tool includes planar (top-down) aerial photographs, satellite images, and a variety of published maps. The historic date range runs from 1867 (just after the formation of Atlantic Petroleum Storage Company) to 2019 (the year the former Atlantic refinery exploded for the last time). There are also up-to-date maps and satellite views. All the cartographic scans have been georeferenced and georectified (pinned and aligned) for easy comparison. Atop each base map you can overlay visual information like ZIP Codes, zoning boundaries, census data, and the “Areas of Interest” (environmental remediation zones) that comprise the former refinery complex. There are also future-oriented overlays that visualize risk scenarios for “100-year floods” and sea-level rise related to global warming. By layering and unlayering, and by zooming in and zooming out, you can see how the built environment has changed over time, and appreciate how those changes relate to social and physical factors. These layered maps have inherent visual interest, but you will gain more from them as you learn about Philadelphia and its fossil fuel history from the textual side of the website.