We see them all the time, but do you ever think about everything these machines do? A fire engine is a combination personnel carrier, tool box and water tanker. Learn all about this amazing 3-in-1 machine.
It's difficult to look up in the sky during a clear day and not see at least one cloudy trail billowing from an airplane. Although they're officially called contrails, some people refer to them as "chemtrails" -- and have interesting explanations for their existence.