Was poking around this antique shop in Ripley, Ohio, and ran across an old Marx tin tank from before 1930.  Seemingly based on a Mk IV, it was missing it's sponson on the left side, and the 6 pounder gun on the right side.  Also missing were the tracks.  But you could still wind it up and the spring motor still turned the wheels!

picture of tin tank

Marx Tin Tank

 

 After admiring this tin toy, I saw this video from The Tank Museum on the pro's and con's (mostly con's) of life inside this tank.  Besides not being able to see out, having no way of aiming the guns accurately, or aiming the tank in any reasonable manner, the heat and carbon monoxide fumes would easily overcome you.  Life in a modern Challenger 2 is light years ahead of these things.  You got to hand it to the guys who had to fight their war inside one of these.