Before 1956, goods used to be loaded onto ships and offloaded directly one piece at a time, which was very slow.
One man, Malcom Maclean, noticed this problem and solved it by inventing the shipping container. A few improvements have been made since then to create the present day ISO container.
At the moment, about 90% of global trade is carried by sea with shipping containers playing a major part. It’s estimated that at any one time there are about six million containers being transported around the world on ships, trucks, and train. Most of these originate from China – where most of the world’s goods (and the containers themselves) are manufactured.
Of these, only a small fraction will be transported back to their port of origin for re-use due to high relocation costs which leads to the “abandonment” of shipping containers in their places of delivery. This phenomenon has made shipping containers abundantly available at low costs virtually everywhere in the world.