To most people a trip through customs is just another stop in an airport or a country's borders. But customs agencies do much more for their countries' governments. In fact U.S. Customs raises more revenue than any agency except the IRS. Find out why and how they do it.
WHAT'S INSIDE: FLIGHT
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Ever wonder what's happening inside that huge jet engine as you're cruising along at 30,000 feet? Jets, helicopters and even some power plants use a class of engine called gas turbines, which produce their own pressurized gas to spin a turbine and create power.
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.