One of the greatest inventions of the 20th century is, perhaps, one of the least obvious.

It does not have the glamour of the ubiquitous smartphone, but it’s arguably just as important. With an estimated 90 per cent of the world’s goods – including foods, technology and medical supplies – transported via sea, the importance of containers to everyday life is stark.

The true value of these steel containers was seen in recent times when a shortage resulted in increased costs and significant delays across the world, affecting shipping interests and consumers alike. The container trade is estimated to account for 60 per cent of all seaborne trade and was valued at approximately US$14 trillion in 2019. It is known to be both reliable and, when compared to airfreight, relatively low cost.

The benefit of containerisation is not just in its standard sizes, which help loading and unloading, but also in the labour required to do these jobs. Additionally, containers make it easier to protect cargo due to their durability and being locked, which adds security throughout the transportation process.

But what is the history of these steel boxes that some estimate to have cut the cost of shipping by at least quarter when first implemented in the 1950s?

Malcolm McLean, an American truck driver, had the idea to standardise containers so they could be stacked better for transport. That thought came in 1937, but the high-school-educated McLean would have to wait two decades before his concept was implemented, when the first container ship left Newark for Houston.

At the time of its growing popularity, the standard size of the container ship was 33 feet in length and eight feet in width and height. The length would soon increase to 35 feet. McLean’s retrofitted oil tankers could only fit 58 containers measuring 35 feet in 1956, a far cry from the industry’s typical vessels now.

Containerised shipping would expand to international routes by the 1960s, quickly gaining popularity for its reduced costs and diminished possible damage.

Today, the container shipping industry continues to grow and carry millions of the revolutionary steel boxes annually, with the largest ships able to carry 24,000 of the now-standard 20-foot or 40-foot-long containers. Even with the larger containers, loading is still relatively simple, fitting comparable shapes on to a vessel designed to accommodate them.

The progress made in transforming the shipping industry through this innovative move would help to increase trade levels, recording almost two billion metric tonnes transported in 2017, a significant increase from the 100 million metric tonnes just 40 years prior.

The carrier shipping industry hit a record-high, combined profit of US$150 billion in 2021, driven by a shortage of containers, increased consumer demand, and congestion at seaports, according to global shipping consultancy Drewry.

While rates have begun to decline from their soaring peak-season and pandemic-driven highs, they are likely to remain elevated throughout this year, and into the next, many experts forecast.

And for those who still doubt its impact, consider that the device you are possibly reading this on was in a container at some point.