One of the world's leading airport operators, BAA owns and manages seven airports in the UK, including London's Heathrow, Gatwick, and Stansted. The company oversees functions such as cargo handling, fire protection, property management, retail operations (including its own World Duty Free stores), and security. In addition, it runs the Heathrow Express rail service to London and works with other mass transit operators. Outside the UK, BAA has a 65% stake in the Naples International Airport in Italy and manages the retail operations at three US airports in Pittsburgh, Baltimore, and Boston. A group led by Spanish infrastructure manager Ferrovial acquired BAA in 2006 for more than ?10 billion in stock.