In Singapore, there's Changi, Morocco has the distinctive Marrakesh Minara, and of course there's the spectacular Zayed International in the UAE.

These places are stunning both inside and out, they're marks of what can be achieved through innovative design.

But you'll notice that none of them are in America.

In fact, no US airport ranks inside the worldwide top 20.

Which might come as a surprise given this place invented the aeroplane and is home to the world's oldest operating aviation hub.

While America has some unique airports, it's fair to say that this type of infrastructure hasn't been its strong suit.

At least, until now.

In the Pacific Northwest, a new terminal has just opened and it's not just one of the most beautiful airports in America, it's up there with the most beautiful in the world.

Sitting on the west coast of the US, Oregon is a haven of natural beauty.

Blessed with both the Pacific Ocean and the Cascade Mountain Range, Beaver State residents really are spoiled for choice.

Zoom in on the map and you'll see Portland, the state's biggest city.

With an unofficial slogan of Keep Portland Weird, you can imagine it's a fun place to spend a weekend.

But first, you'll need to get there, which means passing through Portland International.

Steadfast and reliable, it was always one of America's better airports.

But for years, it's been in desperate need of an upgrade.

The original terminal was constructed nearly 70 years ago in 1956.

Over time, development has seen it spread across 11 separate buildings.

The problem is that they were all designed and stitched together under varying structural and seismic codes.

And that made it near impossible to expand and evolve pretty important features like security checkpoints.

Structural impediments like shear walls and brace frames had to be removed to allow flexibility in case of a need for future adaptations.

Portland Airports, or PDX, was in need of a dramatic refresh.

And so, more than $2BN was spent to modernise the site.

Now, I know that might sound like a lot of money, but by the end of this video, don't be surprised if you're checking flight prices to Portland because this is no minor renovation.

And I really mean that.

The new terminal, which opened earlier this year, is the biggest public works project in Oregon's history.

Not only that, but it's also the largest mass timber project of its kind anywhere in the world.

You absolutely can't underestimate the scale of what's been undertaken here.

But with that said, ZGF Architects and the Port of Portland were keen to make sure PDX still felt accessible and like part of the city.

That meant bringing the outdoors indoors to reflect the natural beauty of the state.

And working with contractors Skanska and Hoffman, that's exactly what they've done.

Pacific Northwest is known as a timber background, a timber land.

So we took inspiration from the forest of our region, inspiration as a walk in the park, and then made sure that they knew that sense of place that this was the Pacific Northwest and not any place else in the country.

It took six years to establish a supply chain to source all the wood for the roof.

And impressively, it was all spruced from within a 300-mile radius of the airport.

With mounting budget pressure, a lot of projects focus on importing the cheapest materials from all over the world, but that's not been the case here.

The focus was on building sustainably using local craft and timber.

Now, budget pressures aren't unique to airport construction.

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Now, let's go back to that beautiful airport.

Walking through the new terminal once all the work is complete, you'd be excused for thinking you're strolling through the city's famous Forest Park rather than rushing to catch a flight.

You'll see more than 5,000 plants, including fully mature black walnut, ficus and olive trees.

They've got access to the natural sunshine that pours in through the 49 strategically placed skylights.

The ceiling is a lattice design spanning nine acres and 600,000 board feet of Douglas fir timber taken from 11 forests.

Coupled with the wooden ceiling, a biophilic approach has been used throughout the terminal for two key reasons.

The first is to sequester carbon emissions and make this project as sustainable as possible.

But also, a natural space is thought to lower blood pressure, making your travel experience more relaxing.

You might not think of an airport as a calming space, but that really is what Portland is going for.

It all sounds great and definitely looks the part, but here's where things start to get really interesting.

For the entire three years that this renovation was taking place on the building footprint, the airport remained open.

These major renovations had to navigate a live operating 500 flights every day.

Now the thought of that might give you a headache, and it probably should because the logistics of running and overhauling an operational airport are incredibly intense.

But here's how they did it.

As I mentioned, the building skeleton is split into various sections with the main terminal in the middle and concourses in the flanks.

Key operations like ticketing and security were moved to the front and sides of the building.

That allowed for demolishing the remainder of the structure behind while keeping the baggage system operational.

Around planes arriving and departing, a section of the airfield became a worksite for pre-constructing that incredible roof.

It was crafted into three massive sections made up of 18 different pieces, with each weighing anywhere from 270,000 to 635,000 kilos.

The biggest section stretched more than 40 by 60 metres.

The roof was built with big steel box girders, so 20 foot by six foot tall box girders, on about a hundred foot grid.

And then in between those girders was built up with curved glulam beams and the mass timber panels on top of it and a roofing on top of that.

And under it was latticed a series of, I think it was three by six lattice to give the beauty of the roof.

To get the roof into position, the sections were separated and drawers slid out from between the girder sections to lift the roof up to 17 metres.

They then had to be moved for about a mile from the construction site at the end of the runway at about one mile per hour.

Each section of roof took around three nights to move, one to drive it to the starting position, the second night to move it halfway and the final night to get it into position.

Once slotted into place, security was able to move into the new building.

Now, it's not every day that you see an airport roof, especially of this size, wheeled across an operating taxiway.

And don't forget that there's one key factor when you're working with wood, it really doesn't like getting wet.

Going through all of this effort for the roof to then expand and not fit into place would have been extremely frustrating, but luckily there was a novel solution.

While we were prefabricating the roof, as soon as wood showed up, we had put a temporary roof on it.

We put a membrane on it to protect it from the elements and that was the primary strategy in keeping it beautiful before we actually moved it into final position.

So a roof for the roof, but this wasn't the only problem the team had to face.

The area underneath construction wasn't empty, it was being used for Portland's baggage system, meaning it was an occupied space.

And so all the fitting work had to happen during terminal downtimes between midnight and 3.30am.

Because we were taking these massive roof sections over an occupied space, during the non-downtimes we had to tie it back in seismically so if there was an earthquake, the roof didn't fall on the people down below it.

Yeah, we forgot to mention another small problem.

Portland is Oregon's most seismically active region, with scientists it will be.

In the event of an earthquake, the whole roof is designed to move as one.

What it's supported on is Y columns, so the columns come up and on the top of each Y is a base isolator, it's a friction pendulum isolator, and so that has been engineered to take the mass at each location, and so at the edges you might have a different size friction pendulum, in the middle you have another size, and those move and it's calculated that the amount of friction force that is taken at each location allows it to move exactly how much it needs to move, and the friction part is what holds it into place.

That allows for 56 centimetres of movement on the friction pendulums.

That means that where the roof touches adjacent surfaces like solid walls and glass, they have to pivot in all directions, and that took some pretty special detailing, mock-ups and testing.

Astonishingly, it's all come together and it really does tick off the big three.

Stunning, sustainable and hard as nails.

This project has been far from straightforward to engineer, but it'll mean Portland International can go about doubling capacity over the coming years.

By 2045, it's hoped that 35 million people will travel through here.

And when they do, they'll be met with a sense of whimsy that really sums up the city and this project.

If you've been here before, you'll be familiar with the famous PDX carpet.

Some would say it's the most iconic in the world.

Stiff competition for those found in the UK's Wetherspoons pubs.

But if you're worried about missing it, don't be, because it survived the renovations.

You'll find recreated sections of the carpet hidden around the airport in relaxing areas ready for snapping shoe selfies, if that's even a thing.

All jokes aside, getting to this point has been a monumental effort.

But the work isn't finished yet and phase two is now already underway.

It includes 11 new restaurants and shops, permanent exit lanes, more escalators to baggage claim and cosy areas for when you're waiting at arrivals.

They're planning to have all the hoardings down and works complete by late 2025.

Only time will tell if PDX can land itself a spot near the top of the world airport rankings.

But whatever happens, it's beautiful.

This place is a shining example in American aviation and a precedent for the future.

This video was sponsored by Brilliant.

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