9 Engineering Marvels From History

We are so used to living in a world of incredible engineering feats that sometimes we forget how much effort it took to get here.

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Whether it’s China building islands in the disputed waters of the South China Sea, the construction of ever-taller skyscrapers in Dubai and Saudi Arabia that stretch nearly a kilometre into the sky, or the development of reusable rockets by SpaceX to slash the cost of space travel, it can feel as if there’s nothing that modern engineers can’t achieve, given sufficient time and money. But it’s still worth reflecting on the incredible feats of the past – those achieved when materials had to be transported by manpower or horsepower, when an abacus was the best way of carrying out calculations, and before the huge advances in materials technology that enable us to reach greater heights today.
In this article, we take a look at some of the tremendous engineering achievements of history, and just what it is that makes them so remarkable for their time.

1.The Great Wall of China (built over centuries from the 7th century BC to the 17th century AD)

Transport route and defensive barricade combined.

The Great Wall of China – called Chang Cheng in China, meaning ‘Long Wall’ – was built over centuries to protect the historical northern border of China from the raiding of the nomadic groups to their north. Hadrian’s Wall, on the former border between England and Scotland, was built on a much smaller scale by the Romans with a similar goal in mind.
The entire wall is over 13,000 miles along and an average of 8 metres high, making it the largest ancient monument in the world. Its age can be disputed; the majority of the wall that remains today is medieval, though parts of the wall date back 2,300 years. While the claim that it’s the only ancient monument that can be seen from space is untrue – you’re either unable to see it, or you’re in a low enough orbit that you can see lots of other things too – its sheer age and size make it a marvel all the same. It didn’t just serve to keep invaders out of China, or a barrier that enabled goods transported along the Silk Road to have customs duties applied, but the wide path along the top of the wall acted as a transport route through what was otherwise often harsh and unforgiving terrain through which military forces couldn’t travel easily.

2. The London Underground (1863)

It’s looking pretty good for its age.

The idea of an underground railway to ease congestion in London was first proposed in the 1830s, but even by 1862, the Times was still describing it as an “insult to common sense.” If you think about it from a Victorian perspective, the idea does seem implausible. Building a huge network of tunnels under an ancient city where the weight of historical building has always made tunnelling a challenge, filling them with steam-powered trains lit by gas lights, with wooden carriages – it sounds like a great way to create the world’s most expensive fire hazard.
But in 1863, the first underground line, the Metropolitan Railway, opened at a cost of £1.3 million – that’s about £149 million in today’s money, which seems quite cheap – and was an immediate success, carrying nearly 10 million passengers in its first year. Trains were every 20 minutes, rising to every 10 at peak times. And all of this was taking place just thirty years after the first passenger railway opened. It had a huge impact on the growth of London as well, allowing poorer workers to enjoy cheap fares, that meant they could live further from the city centre and thereby move out of the worst of London’s slums.

3. The International Space Station (1998)

Just because we can.

One of the great triumphs of engineering through time is how it’s enabled humanity to live in places that by all rights ought to be completely inhospitable. Whether that’s the air conditioning that makes the sweltering heat of central Australia, Saudi Arabia or Arizona tolerable, the heating that means we can endure the far fringes of Canada and Siberia, or the land drainage that enables much of the Netherlands to exist, we’ve made homes in places that only the hardiest of our ancestors could ever have dreamt of.
But there’s nowhere more inhospitable than space. No gravity, no oxygen, with blinding solar flares and radiation, and the crushing cold of a vacuum – it shouldn’t be a place where any individual could survive. But since the year 2000, there have continuously been humans living in space, aboard the incredible collaborative effort of the International Space Station. It was constructed in part by robots, and in part through a series of 127 spacewalks by astronauts, and additional components are being added all the time to replace worn-out parts and to expand the station’s capacity.

4. Hagia Sofia (537 AD)

Impressive both inside and out.

The Hagia Sofia was for a thousand years the largest cathedral in the world, up until the construction of Seville Cathedral in Spain. It was built as the seat of the Eastern Orthodox Church in the 6th century, until the conquest of Istanbul (then Constantinople) by the Ottomans in 1453. From 1931, it became a museum – its many changes of use reflecting the history of Turkey.
It’s of a size that’s incredible for any building not constructed in steel, but that’s not all that’s impressive about the Hagia Sofia. For one thing, it was constructed in just six years, rather than the decades that were the norm for the European Gothic cathedrals that followed it some centuries later. The huge, 31m diameter dome survived just twenty years before it collapsed, but was rebuilt in 562 at an ever greater height of 49 metres. That dome has lasted to the present day, with an elaborate network of windows giving the impression that it’s floating over the interior as the space fills with sunlight.

5. Electrification and the National Grid (1938)

Flouting the rules improved the network.

The history of electrification across the world contains many astonishing stories, regardless of the country you focus on. The creation of the National Grid in Britain is just one example.
By the 1920s, Britain’s electricity was supplied by a patchwork of small networks. This was inefficient and fragmented, leaving some areas without power, and crucially not allowing the redistribution of power over a wider area as and when it was required. By 1933, these had been developed into interconnected regional grids that included 4,000 miles of cabling. But the connections between them existed only for emergencies, and weren’t all used at once. On the night of the 29th October 1937, the engineers who controlled the grid ran an unauthorised experiment in which they connected all the areas together, so that the whole grid ran for the night as an integrated system. They were roundly told off for doing so once the news got out in the morning – but they had proven that the grid had capacity to work on a national scale, and by 1938 it was doing so officially.
This meant that back-up resources could be shared across the country, excess capacity kept to a minimum to save money, surges allowed for and the use of power stations managed so that cheaper or more environmentally friendly power stations could be given priority over more expensive or more polluting ones.

6. Chand Baori (800 AD)

It’s a long walk back up, so bring a picnic!

A stepwell isn’t a deep hole into which you lower a bucket – instead, there are a series of steps that you descend to get to the water level. They were once common in India, but were little known elsewhere.
One such is Chand Baori (baori meaning stepwell) in Rajasthan. It has no fewer than 3,500 steps over 13 storeys, in a geometrical pattern that suggests incredible precision in the building process, and reminds the visitor of an Escher painting. Descending 20m means that the air temperature at the bottom of the well is 5-6 degrees cooler than at the top, so that the evaporation of the water is reduced at times of intense heat. That effect also provided a cool place for locals to stay at times of particularly intense heat – the stepwell was therefore not only a practical way to access and conserve water, but a location for socialising too.
The well’s very survival is astonishing – under the British Raj, the use of stepwells was discouraged as they were thought to be unhygienic. But it’s still here, over a thousand years after its construction, though it is no longer in use as a well.

7. The Golden Gate Bridge (1937)

Workers who fell and survived were rare.

When the Golden Gate Bridge was built, it was the longest suspension bridge span in the world, a record it held until 1964. Every part of its construction represented a challenge, from sinking its foundations into the dangerous waters of San Francisco Bay, to the incredible volume of calculations required to ensure that it could actually be built. Add to that the need for the bridge to survive the regular earth tremors of the San Andreas Fault and it was astonishing that it was built at all.
Also remarkable is the unusual degree of care that was taken – for the time – that construction workers were adequately looked after. A large-scale construction project like this in the 1930s inevitably came with fatalities, but the head of the project, Joseph Strauss, insisted on what was then an innovation of movable safety netting under the bridge to catch workers who fell. Only eleven men were killed in falls from the project, ten on a single day when the netting failed. While this might sound like a lot, nineteen men formed the ‘Half Way to Hell Club’, for those who had fallen and survived – and the fact that there was a club to celebrate it demonstrates how rare it was at the time for a construction project to protect its workers.

8. The Panama Canal (1914)

The canal took centuries to get underway.

The Panama canal plays a vital role in enabling trade around the world. Before its construction, ships travelling from Europe and Africa to the far side of the Americas had to go around the southern tip of South America, a route that was both lengthy and treacherous. As long ago as 1534, the Holy Roman Emperor at the time, Charles V, requested a survey to see if a shorter route through the Americas could be constructed.
But it wasn’t until the late 1800s that construction began. The project was begun by the French, but beset by problems including the deaths of around 22,000 workers from accidents and disease. The project was then bought by the US government, a process that involved US military backing for the independence of Panama from Colombia – interpreted by some as an act of war against Colombia. The emancipation of the West Indies provided a huge amount of labour at a time when Americans were unwilling to emigrate for such a dangerous job. The sheer workload involved was incredible – once the US took over management, they excavated 129,974,326 m3 of material, spending the equivalent of €8.6 billion in today’s money to finish the project in just 10 years.

9. Pont du Gard (50 AD)

So easy, you could build one in the garden!

The Roman aqueduct of Pont du Gard in southern France carried water from a spring at Uzès to the Roman town that became Nîmes. The full length of the aqueduct was a remarkable 50km, but what makes it even more astonishing is that it only descends 17m over its entire length. The bridge that is the key feature of the aqueduct descends by only 2.5cm, which represents a gradient of one in 18,241. This was enough for the aqueduct to carry 200,000 m3 of water a day to the Romans of Nîmes, and to remain in operation for around 500 years, even after it had ceased to be properly maintained.
Considering how the aqueduct was built makes this even more remarkable. It included some 6 ton stone blocks, but very little mortar. The instruments used by the Romans were very basic, including a rudimentary spirit level, measuring poles and a surveying device that allowed for the construction of straight lines and right angles. To put it another way, the entire aqueduct was planned with no device more sophisticated than those that could be found or made in a modern shed – and yet it’s still standing today.
Images: Structure in sky; machine cog; great wall; london underground; space station; hagia sofia; electricity pylons; stepwell; golden gate bridge; panama canal; pont du gard