In this April 9, 2016 photo, with the world's tallest tower фото (photo)

In this April 9, 2016 photo, with the world's tallest tower, Burj Khalifa, in backdrop, a man enjoys an urban zip line attraction in Dubai, United Arab Emirates, Saturday, April 9, 2016. In the air travel hub of Dubai, there's a new way to fly: A zip line run by extreme sports company XDubai. XDubai, which began its operations in 2015, and is associated with Sheikh Hamdan bin Mohammed bin Rashid Al Maktoum, the crown prince of Dubai. (AP Photo/Kamran Jebreili)