When the government of the city of Sandy Springs, in the US state of Georgia, decided to bring in a multinational corporation to run all of the city's services - with the exception of police and firefighting - it effectively became the first fully privatized city in the world. It's a trend that is already spreading fast, with four new cities launched in the last three years, all of them run by the same company, defence contractors CH2M Hill, who have major contracts on the battlefields of Afghanistan and Iraq.