For most of human history, when something was shipped on a boat it was basically just strapped down to the nearest wall or post. Ship's holds were a strange conglomeration of barrels, crates, bags, and god only knows what else. All of the loading and unloading was done by longshoreman who did a good chunk of the work by hand. It took days to load and unload ships, sometimes even longer than the actual sailing time. Theft was not uncommon. All of this combined made the shipping of goods overseas a costly venture, one only available to the richest and largest of companies. However, that all changed in 1956 thanks to some guy named Malcolm McLean.
When Malcolm graduated high school in North Carolina his parents lacked the funds needed to send him to high school, but they did have enough for him to buy a used truck. Malcolm worked the shit out of that old truck, so much so that by the 1950's he had the second largest trucking business in the country. However, this apparently wasn't enough because Malcolm soon after became obsessed with the idea of improving ocean shipping. Seeing the tried and true methods as far too inefficient, Malcolm came up with the idea of packing goods into standardized 20 foot long boxes, which he creatively called containers. While many other groups had tried similar ideas over the preceding decades, it was Malcolm who really went balls to the walls with it. After selling his lucrative trucking firm he purchased a shipping line and whipped himself up a few containers and modified a few ships to carry them.
While originally laughed at when introduced, with most experienced shippers claiming Malcolm didn't know shit about ocean freight, they didn't laugh for long. The loading of a container ship took only 10% of the manpower and 15% of the time as the old method, and at only 3% of the cost. It was a simple concept, which really makes you wonder why no one did it earlier. Shove a bunch of shit in a big metal box, haul it by truck or rail to the port, use a crane to load it on the ship, and there you go.
Why the shippers were more than happy with this new development, the longshoreman and their unions were much less so. The longshoreman unions had fought long and hard for a decent wage, and now some schmuck with a metal box was about to take it all away from them. It's probably important to pause here and mention that when I say hard fought I don't just mean lots of strikes and protests. No, I mean literal street brawls between union members and scabs where some people actually died. The union fights of the early twentieth century were nothing like the union fights of today. They were more like actual revolts against shitty working conditions and the treatment of workers as though they were just cogs in a machine. It was some crazy shit.
Anyways, the longshoreman resisted the introduction of containers for the better part of a decade, but their union leadership eventually came to recognize it was a fight they wouldn't be able to win. In 1966 they negotiated a new contract with significant wage increases and where rather than people getting laid off they were instead paid off to retire early. Even with these stipulations it was a messy transition, resulting in the longshoreman going on strike for 134 days in 1971, the longest strike in US union history. However, the hands of progress were set against them. The union's ultimately lost the strike, though not all of their power thanks to expanding to cover more jobs dealing with the handling and maintaining of containers.
Today some 18 million containers make 200 million trips per year, carrying 90 percent of the world's non-bulk ocean trade. The spread of containers worldwide led to a forced standardization of trade never before seen. For ships to be efficient containers had to be the same set sizes. Since the containers had to be certain sizes this meant that everything else had to be standardized as well. Truck trailers, railcars, even wooden pallets, all had to be certain dimensions. The significant drop in shipping costs and the international standardization led to an explosion in global trade which transformed the globe in ways we are still adjusting to today. A container might be just a box, but its a box that changed the whole damn world.