NEW : Mass media : More than 400,000 people attended the Mass , according to Mexico 's state-run Notimex news agency . More than 400,000 people attend the Mass . NEW : The Pope urges Mexican Catholics to remain true to their faith . Many onlookers wave balloons , flags and banners as the pope arrives . The pope travels to Mexico first .
NEW : Mass media : More than 400,000 people attend the Mass . NEW : The Pope urges Mexican Catholics to remain true to their faith . Many onlookers wave balloons , flags and banners as the pope arrives . The pope travels to Mexico first .