Joe Raedle, Getty Images
August 7, 2012
Miami International Airport's new skytrain is seen on September 16, 2010 in Miami, Florida. The train which is located in the new Concourse D uses four-car trains and carries passengers between stations on the roof of the mile-long concourse. With a capacity to transport 9,000 passengers per hour, the skytrain can get from one end of Concourse D to the other within five minutes.