CityCenter is the biggest, most expensive development in Las Vegas but not everybody is thrilled at the new arrival Detonating a spectacular burst of rooftop fireworks into the night sky, MGM Mirage upped the stakes in Las Vegas forever a couple of weeks ago by throwing open the doors of a new casino, Aria, that sits at the heart of a vast $8.5bn (£5.3bn) complex, CityCenter. It is the biggest, most expensive development in the desert city. But not everybody is thrilled at the huge new arrival on the Strip during such a severe recession .