Stretching 150km along the coast from Two Rocks in the north to Mandurah in the south, the Perth-Peel metropolitan area's length is starkly visible from space.
Many consider it to be the longest city in the world — although it is not an exact science, and Sochi in Russia also has a claim.
Where Mandurah and Yanchep were once holiday destinations for Perth residents looking for a getaway, the city has now stretched to meet them, with bushland making way for suburbia that hugs the coast.
The reason the city became so long is a combination of geography and social preferences since colonisation, according to senior lecturer in archaeology and history at Notre Dame University Shane Burke.
"We're hemmed in on the east by the Darling Ranges, and then we've got this very long area, which is the Swan Coastal Plain," Dr Burke said.
To the north and south of the Swan River (known to the Whadjuk Noongar owners as the Derbarl Yerrigan) there was only flat, sandy country ripe for housing.
"There's no swamps, there's no valleys, there are no other ranges going down to the water, it's flat ground," Dr Burke said.
Sprawl 'baked into urban DNA'
The Perth preference for sprawl and detached housing was also "baked in our urban DNA" by the colonists' experience of British cities, co-director at the Australian Urban Design Research Centre at the University of WA Julian Bolleter said.
"The administrators who planned Perth in the early days were determined that we wouldn't make the mistakes that were made in Europe, with the overcrowded cities in the Industrial Revolution," Dr Bolleter said.
"Perth was a horizontal reaction to the verticality and density of those industrial cities."
Until the 1950s, however, Perth grew relatively slowly.
Areas like Yanchep and Mandurah were considered holiday destinations, and what are now inner-suburbs were once considered the urban fringe.
"Not particularly old Western Australians can remember when Balcatta was the furthest north of the suburbs. I used to go horse-riding in Alkimos [north of Perth] only 30 years ago, there was nothing around apart from the shipwreck off the coast," Dr Burke said.
"We can remember going to Rockingham and then Mandurah for long weekend holidays, now people live there and come into Perth to work."
What turbo-charged the sprawl was population and the creation of the Narrows Bridge interchange, which provided a link across the Swan River and paved the way for the development of the Kwinana and Mitchell Freeways along the coast.
"The freeways were a very, very important component of this, and they could be done reasonably quickly, reasonably cheaply, because of the geographical features," Dr Burke said.
"Even though we curse our sand if we're trying to grow anything, it is very easy to manipulate when putting in infrastructure."
In the decades since, Perth has continued to sprawl and former fishing villages like Rockingham and Two Rocks have been absorbed into the metropolitan area.
Hidden costs in outer suburbia
This growth shows no signs of slowing down, and is not without problems, according to Courtney Babb, senior lecturer in the school of design and the built environment at Curtin University.
"There's a consumer preference for living in areas next to the beach and so we see a lot of young households and first homebuyers in particular looking at land that is further out but located close to key amenities like the beach," Dr Babb said.
"It's a model of growth that's really suited to developers. It's a cheap way of doing it, we've got a very well-oiled development industry that delivers this type of housing.
"There's a range of problems associated with that, a lot of the costs associated with this type of type of suburban living are hidden.
"The transport costs are hidden, there's a lot of environmental costs associated with clearing that land and the biodiversity loss that's associated with that."
Dr Babb said Perth had improved at this kind of development, and learnt from the challenges faced by places like Ellenbrook which were built without public transport infrastructure and other community amenities, a plan the state government is now attempting to address with the Metronet train network.
Car dependence still an issue
"There are still substantial problems about the amount of car dependence and the environmental quality of these suburbs," Dr Babb said.
"Metronet stations in these key growth corridors are a really positive thing, but we also need to need to think about other aspects of transportation, walking and cycling for local areas and neighbourhoods and improving those links within these subdivisions and the connections to the stations as well."
He said if Perth wanted to stop sprawling and building new train lines, the city would have to get more serious about suburban infill and adding more dwellings to existing suburbs.
"At the moment, it's not looking particularly promising that we would avoid that fate," Dr Bolleter said.
"We have one of the lowest targets for infill development around the nation, which is 47 per cent infill development.
"According to the most recent data we're doing about 29 per cent, so that means the substantial majority of development we're doing is suburban expansion."
Making plans a reality
Dr Bolleter said that while good plans existed for fitting more people into the city's existing footprint, making them a built reality was a different story.
"A planner can draw a dotted line around a centre like Armadale or Midland and say: 'Insert density here'," he said.
"But they're not actually generally delivering that density, it is up to a private developer to deliver it, who may or may not be interested in that, and the business case may not stack up.
"There is often a slippage between what is planned and what actually occurs on the ground.
"Quite rightly, the state government is attempting to do density around transit nodes, but the reality is a lot of densification is just occurring in a fairly ad-hoc way through the back gardens of suburbs like Bayswater and Beechboro and Bassendean."
There is no clear sign of how the sprawl will stop. In the 1970s, planners expected Joondalup, 30km north of the CBD, to be the northern centre.
Now, it is Yanchep, another 30km further north.
"There is always that possibility beyond 2050 that we re-think our frame that Perth will get longer, but I think there needs to be a real shift at some stage so that we do attract the infill development," Dr Babb said.
Stan Shaw is exploring the length of Perth all week on ABC Radio Perth breakfast, broadcasting from Mandurah, Mt Pleasant, Joondalup and Yanchep from March 28-31.
