Esri GeoInquiries
Esri (the makers of ArcGIS) GeoInquiries offers "collections" of stories that use maps to teach lessons on a variety of topics, from environmental and earth science to transportation to geography.
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For more about Esri's work in K-12 and STEM education, go to https://www.esri.com/en-us/industries/education/schools/our-story.
If you're interested in using ArcGIS in your classroom, Esri offers the Mapping Hour to learn about using ArcGIS for K-12 education. Get started at https://mappinghour-k12.hub.arcgis.com/.
Finally, ArcGIS is offered free to schools for instructional purposes: https://www.esri.com/en-us/industries/education/licensing