... in 1955, Malcom P. McLean, a trucking entrepreneur from North Carolina, USA, bought a steamship company with the idea of transporting entire truck trailers with their cargo still inside. He realized it would be much simpler and quicker to have one container that could be lifted from a vehicle directly on to a ship without first having to unload its contents.
This gave birth to "intermodalism", the theory that shipping efficiency could be vastly increased when the same cargo can be transported, with minimal downtime, between the sea and land.
I'm not an expert on any of this, but it would seem to me the invention of containerization has to've had an enormous effect on global trade.
Containerization is estimated to have increased bilateral trade by 320% over the first 5 years after introduction, and by 790% over 20 years.
Source:http://www.economist.com/blogs/economist-explains/2013/05/economist-explains-14
When Malcom McLean invented containers, in 1956, he found that loading and unloading costs (from ships) went from $5.82/ton to $0.16/ton.
Losses from theft plummeted. Insurance costs fell. Turnaround time for ships reduced as loading went from 1.7 tons/hr to 20 tons/hour. Ships became larger, transporting more cargo with relatively less fuel and crew. Containers also had similar benefits inland, when being loaded on trains or trucks.
The power of dock workers was reduced (as were their numbers), and the number of strikes went down, further contributing to reduced costs.
As the costs of transport fell, it became profitable to trade more and more goods that could not have been profitably internationally transported before.