As the Line gigaproject continues to grow in the Saudi desert, some new construction details have been announced that highlight the mind-boggling challenge of turning a huge tract of rugged landscape into a futuristic megacity, including its reported use of one fifth of the entire world's currently available steel.To recap, the Line is the key part of Saudi Arabia's Neom project, which is itself part of a larger push to transform the country's predominantly oil-based economy into a tourism-focused one as fossil fuel use is inevitably reduced in the coming years.The plan is for the Line to eventually have a...