HIROSHIMA, Japan - President Barack Obama says the world has a shared responsibility to ask how to prevent the suffering that took place in Hiroshima more than 70 years ago from happening again.
    
Obama spoke today at Hiroshima Peace Memorial Park in Japan, making him the first U.S. sitting president to visit the city since the U.S. dropped an atomic bomb in 1945.
    
Obama then spoke briefly with some Hiroshima survivors.