Experts studying a manual on artillery and siege warfare from around 1530 made a rather startling discovery recently.
The images from the manual, written by artillery expert Franz Helm, from Cologne, Germany, appear to show cats and birds being strapped with jet packs and propelled towards a castle.
The manual basically recommends capturing a cat from enemy territory, attaching a bomb to its back, lighting the fuse and hoping it runs back towards the enemy.
