Picture of the Day 07/09/25 - Wikimedia Commons
• 07/09/25 at 12:16PM •Rifling of a M75 cannon (year 1891, Austro-Hungarian). Exposition of Ljubljana Castle (Ljubljana, Slovenia). The photo was made by macro stacking of 43 pictures.
Petar Milošević, CC BY-SA 4.0, via Wikimedia Commons. View source.