Saudi Crown Prince Mohammed bin Salman has promised to prove wrong sceptics of the multibillion-dollar mega-city Neom.
Neom includes the 170km strip of vertical city, The Line, which Prince Mohammed announced in 2021.
He told Discovery Channel that the mega-project would make money, meet demand and reinvent cities.
Since its announcement, The Line has attracted interest from all over the world, including from sceptics who call it "too ambitious".
On Discovery Channel, Prince Mohammed, who is leading the kingdom's Vision 2030, addressed the critics and revealed details of the "city of the future" in the north-west of the country, which will be free of cars, streets and carbon emissions.
"They say a lot of projects in Saudi Arabia cannot be done. They're 'too ambitious'," he said of Neom.
"They can keep saying that and we can keep proving them wrong."
The aim is for Neom to have 10 million residents when completed and Prince Mohammed said Saudi Arabia wanted to “think from scratch" to build on the empty land.
He said the Saudi population would jump from 33 million to between 50 and 55 million by 2030.
"In 2030, we will reach the full capacity of Saudi Arabia’s current infrastructure," Prince Mohammed said. "That raises a very important question – that we need to create new cities.
"When it comes to engineering and design [we] also need art. The whole city is a piece of art. It's amazing, massive and huge … and very do-able."
Prince Mohammed said the kingdom held a competition in which the "best designers on the planet" pitched ideas for the city, but all except one pitched a line instead of a circle, which is the usual model of cities.
He said when he saw the initial plans for The Line, with the width of 2km, he asked the team if they could "flip it" instead with two towers extending down the city.
"North-western Saudi Arabia is untouched," Prince Mohammed said.
"It's empty [and] has a mix of topography, from mountains to islands, beaches, dunes, to oases, corals, skiing to diving," he said, calling it "the place".
"Neom will compete with Miami in terms of entertainment, culture, sports and retail."
Saudi Arabia is a G20 country with "financial capabilities, land, stability and infrastructure" to build The Line in Neom, he said.
"Saudi Arabia wants to create a new civilisation for tomorrow. We encourage other countries to do the same for a better planet. It's going to be something new and creative."