Seen at the Galleria Michelangelo in Florence Italy (but likely to be seen at a traveling exhibit near you), it’s a wooden model of a da Vinci armored car:
Leonardo drew up the design for this war machine in 1485, likely as part of a portfolio presented in a job request to the Duke of Milan. At full scale, this unusual little creation would have held eight men turning cranks in order to turn its four wheels, and firing its 30 light cannons.
Historically, it was the first of its kind — but wouldn’t have worked as-is. Putting so much weight on a few small wheels, it would have quickly imbedded itself in any but the hardest and flattest terrain. At a more basic level, though, the mechanism as it was sketched would have turned the wheels in opposite directions.