In our time of looming ecological disaster, radical minds are needed to rethink the way we live. In Saudi Arabia, NEOM are building a futuristic new city: The Line. The Line will consist of two gigantic, unbroken rows of skyscrapers, with living space in-between. Nicknamed 'the groundscraper', The Line is planned to be taller than any building in Europe, Africa or Latin America - and 10 times denser than Manhattan, with nine million people expected to live inside. We meet the architects behind The Line, and take a journey to the city of the future.