WWTBAM Bored

Fanciful illustrations from a circa-1530 manual on artillery and siege warfare seem to show jet packs strapped to the backs of cats and doves, with the German-language text helpfully advising military commanders to use them to "set fire to a castle or city which you can't get at otherwise."

Digitized by the University of Pennsylvania, the unusual, full-color illustrations recently caught the attention of an Australian book blog and then found their way to Penn researcher Mitch Fraas, who set out to unravel the mystery.

"I really didn't know what to make of it," said Fraas, a historian and digital humanities expert at the Penn library. "It clearly looks like there's some sort of jet of fire coming out of a device strapped to these animals."