A banner advertises plans for a greener and more sustainable city. The crown prince’s next grand plan is to defy the skeptics and turn Riyadh into a greener, cooler city for twice the population. On Riyadh’s King Abdulaziz Road, construction workers sweep sand off a brand-new sidewalk. A gardener pops a spindly plant out of a plastic pot and gives it a new home in the ground, smoothing the soft red earth with his hands. Behind them, 15-foot-high banners advertise the future gardens and canals of King Salman Park, a plan to turn an air base in Saudi Arabia’s desert capital into a public green space four times bigger than Central Park in New York. Saudis have gotten used to breakneck change over the past five years under Crown Prince Mohammed bin Salman, whether it’s the shock therapy to turn the kingdom into a post-oil economy, a high-tech city […]