Map of the second ring of fortifications of Lyon (France), the Séré de Rivières defensive system. Legend:

 Fort
 Artillery battery
 Redoubt
 Warehouse
* File:Lyon Rohault de Fleury fortifications map-blank.svg by [[:User:|Sémhur (talk)]] under license CC-BY-SA 2.0
See the image in its original context on the OpenStreetMap wiki page for Lyon.
OpenStreetMap contributors and Sémhur