thumb|Gros Caillou '''Gros Caillou''' (literally "big pebble") is a landmark of the French city of Lyon in the neighborhood Croix-Rousse. The rock's mineralogical composition suggests it is a glacial erratic, and would have been transported from the nearby Alps by slowly moving glaciers.
== Localization ==
Originally, Gros Caillou was located at the end of Boulevard de la Croix-Rousse, constructed in 1865, and the boundary between the 1st arrondissement (Croix-Rousse hill) and the 4th arrondissement (Croix-Rousse plateau). Until it was annexed in 1852, the Croix-Rousse Plateau was a separate city. Thus, the location of Gros Caillou at that intersection became a unifying symbol. At the beginning of the 21st century, an underground parking lot and green area took over this area and Gros Caillou was relocated 30m into the 1st arrondissement.
== History == Gros Caillou is a metamorphic Triassic quartzite, typical of the alpine regions of Haute-Maurienne and Haute Tarentaise. It is rock that was displaced by glaciers over 200 km during the Riss glaciation (around 140,000BC).<ref>Source : {{cite web |url=http://planet-terre.ens-lyon.fr/planetterre/objets/img_sem/XML/db/planetterre/metadata/LOM-Img62-2003-12-01.xml|title=Le Gros Caillou de la Croix-Rousse |last=Thomas |first=Pierre |date=30 April 2003 |access-date=23 November 2015 |language=French |trans-title=the Gros Caillou of the Croix-Rousse}}</ref>
The discovery of Gros Caillou dates back to 1861 during drilling of the tunnels of a funicular linking downtown Lyon to the Croix-Rousse plateau. The drilling had to be interrupted as the workers were blocked by an extremely hard rock, which they could not break.<ref>Source : {{cite web |url=http://www.la-croixrousse.com/patrimoine-culturel |title=Patrimoine Culturel |access-date=24 November 2015 |language=French |trans-title=Cultural heritage |archive-url=https://web.archive.org/web/20151126054606/http://www.la-croixrousse.com/patrimoine-culturel |archive-date=26 November 2015 |url-status=dead }}</ref>
After many attempts and work stoppages, Gros Caillou was eventually excavated, becoming a symbol of not only the annexation of Croix-Rousse, but a symbol of the perseverance of Lyon's inhabitants. Had the funicular not been under construction, Gros Caillou would never have been found and relocated to the east side of Croix-Rousse boulevard, where to this day it overlooks the Rhône River and the Alps.
== Gallery == <gallery style="text-align:center;" mode="packed"> Lyon - Gros Caillou.jpg|The Gros Caillou at the beginning of the 20th century. Gros Caillou Lyon Croix-Rousse.JPG| Lyon gros caillou 073.JPG|The Gros Caillou from a different angle. File:Lyon (9 août 2013) 081.JPG|The Gros Caillou is a playground for local children. Lyon 04 - Vogue des Marrons - Place du Gros-Caillou (nuit).jpg|The Gros Caillou by night. </gallery>
== References == {{reflist}}
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== See also ==
Category:Landmarks in France Category:Buildings and structures in Lyon