Energy companies have partnered with the military many times in the past, too, which brings us to the Holt Gas-Electric Tank, the first American-made tank. Take a look in this energyTHEN.

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[ASSURAS] It made its debut during World War I and was built to hold six soldiers. Developed by tractor-maker Holt Manufacturing and General Electric, it relied on four-cylinder diesel engines to power two electric motors in order to move the giant tracks. Only one was built. But it didn't move well and never saw combat because the war ended before improvements could be made.

The military tried another electric tank in World War II, but it was an early casualty also, never making it to the battlefield.