Milan Skocovsky opens the 6.5 tonne door of the former Soviet Army nuclear weapons depot near the village of Misov, 90 km (56 miles) southwest from Prague, May 16, 2013. One of the former communist Czechoslovakia's most mysterious and secret spots built to shelter for Soviet nuclear warheads is being turned into a museum, inviting visitors to learn about the nuclear race in the Cold War. Picture taken May 16, 2013. To match story CZECH-SOVIET/MUSEUM REUTERS/Petr Josek (CZECH REPUBLIC - Tags: MILITARY POLITICS SOCIETY TRAVEL) 

International Atomic Energy Agency (IAEA) Director General Mohamed ElBaradei (C) walks with Iran's Atomic Energy Organization's Mohammad Saeedi (L) as he arrives at the International Imam Khomeini airport in south of Tehran January 11, 2008. ElBaradei arrived in Tehran on Friday to discuss outstanding questions about Iran's nuclear ambitions, a programme the West fears will ultimately yield warheads. REUTERS/Raheb Homavandi (IRAN) 

International Atomic Energy Agency (IAEA) Director General Mohamed ElBaradei (L) descends an escalator with Iran's Ambassador to the IAEA Ali Asghar Soltanieh (R) and Iran's Atomic Energy Organization's Mohammad Saeedi (2nd L) at the International Imam Khomeini airport in the south of Tehran January 11, 2008. ElBaradei arrived in Tehran on Friday to discuss outstanding questions about Iran's nuclear ambitions, a programme the West fears will ultimately yield warheads.REUTERS/Raheb Homavandi (IRAN) 

International Atomic Energy Agency (IAEA) Director General Mohamed ElBaradei (C) walks with Iran's Ambassador to the International Atomic Energy Agency (IAEA) Ali Asghar Soltanieh (R) as he arrives at the International Imam Khomeini airport in south of Tehran January 11, 2008. ElBaradei arrived in Tehran on Friday to discuss outstanding questions about Iran's nuclear ambitions, a programme the West fears will ultimately yield warheads. REUTERS/Raheb Homavandi (IRAN) 

International Atomic Energy Agency (IAEA) Director General Mohamed ElBaradei arrives at the International Imam Khomeini airport in south of Tehran January 11, 2008. ElBaradei arrived in Tehran on Friday to discuss outstanding questions about Iran's nuclear ambitions, a programme the West fears will ultimately yield warheads. REUTERS/Raheb Homavandi (IRAN) 

International Atomic Energy Agency (IAEA) Director General Mohamed ElBaradei (C) walks with Iran's Ambassador to the International Atomic Energy Agency (IAEA) Ali Asghar Soltanieh (R) and Iran's Atomic Energy Organization's Mohammad Saeedi as he arrives at the International Imam Khomeini airport in south of Tehran January 11, 2008. ElBaradei arrived in Tehran on Friday to discuss outstanding questions about Iran's nuclear ambitions, a programme the West fears will ultimately yield warheads. REUTERS/Raheb Homavandi (IRAN) 

Anti-North Korea protesters wearing masks of North Korean Leader Kim Jong il (L) and South Korean President Roh Moo-hyun hold a mock nuclear weapon at a demonstration against the upcoming inter-Korean summit in Seoul September 30, 2007. The inter-Korean summit will be held in Pyongyang on October 2-4. The letters on the mock read, "Nuclear weapon". REUTERS/Han Jae-Ho (SOUTH KOREA) 

France's missile M51 soars into the air during its first test in Biscarosse November 9, 2006. In project to modernise France's nuclear arsenal, the M51 will weigh half again as much as the existing M45, allowing it carry up to six warheads over an intercontinental range. REUTERS/Regis Duvignau (FRANCE) 

Damon Albarn, lead singer of the British music group Blur, attends the first stage of a four-day CND (campaign for nuclear disarmament) march in London, April 9, 2004. The protest is due to finish on Monday at Aldermaston to the west of London, the site of the Atomic Weapons Establishment, which provides the warheads for Britain's nuclear deterrent. REUTERS/Hugo Philpott HP/MD/WS