In this Wednesday, July 25, 2012 photo, a blimp flies in the sky as the sun sets behind the Olympic Stadium at the 2012 Summer Olympics, in London. A world city that needs no introduction, but scarred by terror bombings, riots and economic crisis since picked as Olympic host seven years ago, will launch the 2012 summer games with a spectacular opening ceremony Friday faced with a unique challenge: to be as memorable as Beijing's planet-wowing, money-no-object Olympic extravaganza of 2008. (AP Photo/Ben Curtis)