The Merthyr Rising occurred in south Wales. British militia killed 24 Welsh rioters and eventually sentenced and executed Dic Penderyn (Richard Lewis), who became a working-class martyr.
Image: A plaque commemorating the execution of Dic Penderyn. This image is in the public domain in the United States as it has a permissive Creative Commons Licence. Courtesy of Open Plaques: https://s0.geograph.org.uk/photos/94/78/947861_eb5d7908.jpg