Girls pose during a photocall to promote the Big Royal Wedding Sleepover at “Camp Royale” on Clapham Common on March 8, 2011 in London, England. The “Pop Up” campsite will cater for up to 10,500 people between April 28 and May 1 to coincide with the weekend of the Royal Wedding on April 29. (Photo by Dan Kitwood/Getty Images). LONDON, ENGLAND – MARCH 08 2011

A CRH train is seen passing through Nanjing South Railway Station, which is part of the Beijing-Shanghai High-Speed Railway Line, on March 27, 2011 in Nanjing, Jiangsu Province of China. The High-Speed railway line is 1,318 kilometres long, running between Beijing and Shanghai. The line will open on June 10, 2011. (Photo by ChinaFotoPress/Getty Images)

In this image provided by the Ministry of Defence, Prince William takes the controls of a Sea King helicopter on April 14, 2011 in Holyhead, Wales. Search and rescue co-pilot Prince William, based at RAF Valley will marry his fiancee Catherine Middleton in Westminster Abbey in London on April 29, 2011. (Photo by MoD Crown Copyright via Getty Images)

The finishing touches are made to a giant sculpture on the Hayward Gallery entitled “Urban Fox” and made from straw bales on April 18, 2011 in London, England. The sculpture features in the Southbank Centre's 60th anniversary celebration of the 1951 Festival of Britain. The celebration will feature various cultural and creative events and runs from April 22 until September 4, 2011 at London's Southbank Centre. (Photo by Oli Scarff/Getty Images)

RAF volunteers from stations across the UK, who will be acting as the lining party during the Royal Wedding, practice drills in the Parade square at RAF Holton on April 26, 2011 in Aylesbury, England. The members will make up the Queen's Colour Squadron, and will be lining the route between Buckingham Palace and Westminster Abbey during the wedding of Prince William and Catherine Middleton on April 29, 2011. (Photo by Dan Kitwood/Getty Images)

Moroccan-born pole dancer Karima El Mahroug, nicknamed “Ruby the Heart Stealer” attends the traditional Vienna Opera Ball at the state opera on March 3, 2011 in Vienna, Austria. (Photo by Andreas Rentz/Getty Images)

The Sydney Skyline is seen before the lights are switched off for Earth Hour on March 26, 2011 in Sydney, Australia. Earth Hour encourages individuals around the world to turn off their lights for one hour at 20:30 local time on March 26, 2011 to take a stand against climate change. The largest Earth Hour was in 2010 when 128 countries participated.

A visitor to ''The Cult of Beauty: The Aesthetic Movement 1860-1900'' exhibition at The V&A Museum looks at sculptures by Thornycroft (L) and Watts on March 30, 2011 in London, England. This exhibition brings together for the first time many masterpieces in painting, sculpture, design and furniture as well as fashion and literature and runs from April 2nd to July 17th 2011.