I take it you've never heard of Las Vegas? It was nothing but desert before the Hoover Dam was built in 1930. Now, the Las Vegas metro area has a population of over 2 million people, and the city produces billions of dollars in gaming revenue each year.
Mmmh .. to build a city in the desert - first of all you need a desert. This is a little difficult for Central Europe. And by the way - the UAE did not build the city. The sheiks gave money to 1. world industries to plan and perform the job.