Hostesses in black robes and headscarves give instructions to foreign visitors trying out a simulator at a Formula-E race on the outskirts of Riyadh, Saudi Arabia on Saturday, Dec. 15, 2018. Men and women mingled freely during the event, a scene that would have been unthinkable in the ultra-conservative kingdom until recently. (AP Photo/Karin Laub)

A man watches the sun setting over Dhiriyah, a UNESCO World Heritage site that includes a 17th-century fortress, mosques and clay-colored structures just outside of Saudi Arabia's capital of Riyadh on Sunday, Dec. 16, 2018. (AP Photo/Karin Laub)

In this Dec. 15, 2018 photo, electric cars are powered before one of the races at the Formula-E held on the outskirts of Riyadh, Saudi Arabia. A Formula-E car race and concerts where men and women mingle freely epitomize the reform agenda of Saudi Crown Prince Mohammed bin Salman. But there’s a hard limit to the reforms _ as revealed by the brutal killing of Saudi critic and writer Jamal Khashoggi by Saudi agents close to the crown prince in October and the reported torture of five women’s rights activists in detention. The crown prince presides over a nation where he alone defines the pace and scope of change. (AP Photo/Aya Batrawy)