About 90% of everything traded between countries - clothes, electronics, food, toys, car parts - travels at some point on a container ship. Modern giants stack metal boxes more than 20 high and 24 across on their decks, plus more below. The biggest can carry over 24,000 containers, enough cargo to fill 12,000 trucks on a highway.
Containers themselves were invented in the 1950s and changed shipping forever. Before that, dockworkers loaded cargo piece by piece. Now a crane can lift one standard box off a ship and onto a truck or train in under a minute. Ports redesigned themselves around containers, and global trade exploded.
The ships are huge but the crews are tiny - sometimes only about 20 people running a vessel longer than three football fields. They burn a thick, sticky fuel called bunker fuel, which is cheap but polluting. New ships are starting to run on cleaner fuels or even sails, trying to cut the giant carbon footprint of moving the world’s stuff.
