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

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)

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)

Cat lounges and makes itself at home at the new Cat Café by Purina ONE on Wednesday, April 23, 2014 in New York. (Photo by Amy Sussman/Invision for Purina ONE/AP Images)

Somali men carry swordfish from the sea to a market in the capital Mogadishu, Somalia Thursday, April 23, 2015. (Photo by Farah Abdi Warsameh/AP Photo)

Cracks are seen on one of the shrines at Swoyambhunath Stupa, a UNESCO world heritage site, after Saturday's earthquake in Kathmandu, Nepal April 28, 2015. (Photo by Navesh Chitrakar/Reuters)

General view of the entrance to the Swarowski Crystal World museum on its reopening day following renovation, in the western Austrian village of Wattens April 30, 2015. (Photo by Dominic Ebenbichler/Reuters)

Hungarian Puli sheep dog, Fee, jumps over a hurdle during a preview for a pedigree dog show in Dortmund on Thursday April 24, 2008. (Photo by Frank Augstein/AP Photo)