California Barrel Cactus (Ferocactus cylindraceus). You can see it leaning towards the south, which gives it the name "Compass Barrel". It is endemic to the south-western parts of the USA and northern México. (1190k)
Here are the pictures of California Barrel Cactus (Ferocactus cylindraceus) with links to the pages on which they appear, links to the full sized picture, and the description of the picture with links to the entry in iNaturalist (inaturalist.org)
All pictures are © Dr. Günther Eichhorn, unless otherwise noted.
USA Nature
Dr. Günther Eichhorn Travel Website
Soaring website