World's biggest mobile fair in Barcelona kicks off On the opening day of the world's biggest mobile fair in Barcelona, Spain, Mozilla Foundation announced Sunday the launch the widely anticipated Firefox operating system for smartphones in a direct challenge to the duopoly of Apple's iOS and Google's Android, while other companies presented transparent photovoltaic technology that allows mobile phones to be charged by sunlight, phones tailored for senior citizens and emergency mobile phones with up to 15 years of battery life. Images and soundbites