The building you were born in, the one where you work, and every road you’ve ever traveled, and every bridge you’ve ever crossed – they’re all the creations of civil engineers. Civil engineering is one of the most ancient types of engineering, focused on structures and buildings of all kinds. And it’s the accomplishments of civil engineering that our world is built on. Literally. Society wouldn’t be the same without them.

If you want to think like a civil engineer, imagine that you’ve just discovered an island – a place that no other human had ever seen or set foot on. Like any good explorer, you check out this mysterious island, to see what it has to offer, as well as what it lacks. Is there food available? And if so, where does it grow? What about the water supply? What’s the weather like? Is the terrain easy enough to travel over? Let’s say that after answering all of these questions, you decide that the island is habitable. So, what if you tried to build a city there? What kinds of structures would you need? How would you build them? And would it matter what order you build them in? How do you plan an entire city?

[Theme Music] We’ve been using some kind of civil engineering for most of our history. We’ve built shelters to protect ourselves from the weather and used tree trunks as makeshift bridges to cross rivers. Our earliest ancestors probably weren’t doing any calculations, but they were using engineering to find solutions to their problems. And we can find one of the world’s first notable civil engineers about 5,000 years ago in Egypt. This is where we meet Imhotep, the planner of the first Egyptian pyramid. He was a government official, a sage, and even eventually worshipped as the Egyptian god of medicine. And to that already impressive resume, we can add the title “chief of works”, or what we’d call him, “engineer.” Imhotep helped oversee the building of the Step Pyramid of Saqqara, constructed in the 27th century BCE. The limestone-based pyramid was about as tall as a modern 18-story building, at around 60 meters, or 200 feet high. And its design and construction helped pave the way for other great civil engineering marvels like the Great Pyramid of Giza. This was where we really saw the first two fields of civil engineering come together: structural engineering and construction engineering. Both are similar, but structural engineering focuses more on the design and framework of structures, while construction engineering is more involved with actually building the structure.

We’re going to need to use both of these disciplines if we’re to have any hope of creating a city on our island. Let’s suppose we use Imhotep’s blueprints and build a few pyramids here. After that, let’s move on to something that we’ll definitely need: a public water supply. For this, we can find inspiration in Mesopotamia around the year 691 BCE. This was where the Aqueduct of Jerwan, one of the world’s first notable public water works, was built by Assyrian engineers. It was made of millions of stones to carry water from the mountains to the city of Nineveh. Since having water will be crucial to our city, we’ll want a public water supply, too, and a more modern aqueduct system of pipes and tunnels to carry water to homes and buildings.

And speaking of thinking ahead! If you want to learn how to actually map out your future community, you have to learn from Hippodamus of Miletus. He lived in Greece around 460 BCE, and can be called the father of city planning. Much of what we know about him comes from Aristotle’s work, known as Politics. Aristotle thought Hippodamus was weird, because he wore his hair long and wore flashy jewelry with cheap clothes. But even Aristotle would agree that Hippodamus was also extremely influential. Many aspects of urban design that we now take for granted – like rectangular city blocks and straight streets with avenues at right angles – can all be attributed to him. In fact, this layout is often known as the Hippodamian plan, and it also involves dividing up cities into different parts for different purposes. This was very different from previous designs in his day, which often involved streets that curved, twisted, or ran into dead ends. So, let this be a lesson for your island community: If you’re gonna build a city, you need a plan. And if you don’t plan ahead in civil engineering projects, you could end up with things in all the wrong places. After all, you don’t want farms and crops near sewage treatment plants, or schools next to a noisy airport.

Now, we should also take a page from the Ancient Romans. They were some of the greatest engineers of the past, with roads, tunnels, bridges, and plenty of aqueducts and water supplies throughout their lands. Their works are great examples of the third field of civil engineering: transportation. Good infrastructure will let you use as much of the island as you can, for example, roads that run over hills and valleys, and bridges for crossing lakes and rivers. Part of what made Romans so prolific in their city designs was the clever use of their environment. They mixed lime, small rocks, and volcanic ash to make their own form of concrete, which allowed them to build impressive structures like the Pantheon and the Colosseum. Since I don’t see many volcanoes on our island, we should stick with a more modern kind of concrete, like the one patented in early 19th century England by Joseph Aspdin. He used finely ground stone and clay to make what he called “Portland cement” because of its resemblance to the limestone of Portland, England.

But there are few better lessons in the importance of building materials than the Eddystone Lighthouse. The tale of this structure begins at England’s Eddystone Rocks in the late 17th century. And like most great engineering stories, it started with a problem: The rocks, off the coast of Cornwall, were causing lots of shipwrecks. Henry Winstanley was a painter, builder and merchant who lost two ships on these rocks. So he built a lighthouse on them. It was octagonal, made of wood, and lasted for a few years until a storm came through and destroyed it. But another builder soon constructed a second lighthouse, also made of wood. This one lasted for around 50 years, but was then burned to the ground from the spark of a candle, a reminder of how susceptible wooden structures are to fire. It became apparent that the wood wasn’t working for this lighthouse, so a new generation of engineers had to do something different. That’s where John Smeaton came in. Instead of wood, he began building a lighthouse in 1756 made from hydraulic lime, a type of concrete that sets under water. This allowed for his lighthouse to last for more than 120 years, until 1877, when it was dismantled because the rocks beneath the tower were beginning to destabilize. But Smeaton’s success in meeting this challenge set the stage for using cement and concrete in structural building. Smeaton is actually the first to label himself as a “civil engineer.” And ever since, engineers have had him to thank for separating the civilian side of engineering from the military side. We’ll also want to thank him for the lighthouse we’re going to build on the south side of our island to warn travelers of the dangerous reef.

But we’re missing something very important: sanitation. Some form of sanitation has been used since ancient times. But a more modern form of environmental engineering began when Sir Joseph William Bazalgette designed a sewer network for central London. His network helped relieve the city of its cholera epidemic by treating the water and cleansing the polluted River Thames, which took nearly 20 years to complete, and he was eventually knighted for his work. This all led to the continued practice of treating drinking water and sewage, which will be crucial to maintaining public health on our island.

There are still more things that civil engineering can do for our city, like the construction of dams and canals, which falls under hydraulic engineering. And then there’s working with the rock and soil of the Earth so our structures are built on the right foundation, which is the work of geotechnical engineers. So the idea of creating a city from an empty patch of wilderness shows you how many problems present themselves, and how different kinds of civil engineering can solve those problems. We’ve achieved civilizations – whole societies – because of civil engineering. We’ll go into more detail in future episodes that will give you an even better idea of the work behind civil engineering. But this is just enough to give you – if you will – a solid foundation. Today we learned all about many of the facets of civil engineering, including structural and construction engineering, city planning, transportation, and sanitation. Next time, we’ll explore the mechanical side of engineering, including its history and the types of work that you might do as a mechanical engineer. Thanks for watching and I’ll see you then.