US President Barack Obama has mapped out his vision of a nuclear weapons-free world. Speaking in the Czech capital Prague, President Obama said that -- quote -- "As the only nuclear power to have used a nuclear weapon, the United States has a moral responsibility" to lead the way. He went on to denounce what he called "fatalism" over the issue of nuclear weapons proliferation. After his speech, the president took part in a mini EU-US summit that was also held in Prague, before heading for his next port of call: Turkey. +++SYN-MAZ+++