Aerial dancers from Voloa, perform a dress rehearsal ahead of their performance at the opening night of Salisbury International Arts Festival on May 20, 2011 in Salisbury, England. The 39th Salisbury International Arts Festival runs from tonight until Saturday 4 June 2011 and features a programme of theatre, dance, circus, film, music, comedy and spoken word in locations around the historic city, from Salisbury Cathedral to Stonehenge. (Photo by Matt Cardy/Getty Images)

Women talk during a Slutwalk march for the right of women to wear what they want without harassment on May 28, 2011 in Melbourne, Australia. The Slutwalk began with a small protest in Toronto, Canada, when women marched against a policeman who claimed he was told women should “avoid dressing like sl*ts in order not to be victimized”. Slutwalks are scheduled for Adeleaide and Sydney as well as other cities in North America and Europe. (Photo by Scott Barbour/Getty Images)

In this handout photo provided by the Helmholtz Center for Research on Infectious Diseases an EHEC bacteria is visible on May 30, 2011 in Berlin, Germany. German health authorities have attributed at least 14 deaths within the last two weeks to an outbreak of enterohemorrhagic E. coli, also known as the EHEC bacteria. (Photo Courtesay Manfred Rohde, Helmholtz-Zentrum fuer Infektionsforschung (HZI)/Getty Images)

Masaaki Nagumo controls the Land Walker robot at Sakakibara Kikai Co., Ltd Headquarters on May 12, 2005 in Maebashi, Japan. The two legged robot stands at 3.4 metres high and weighs 1000kg. The Land Walker is available to buy for 36,000,000 yen (approximately US $340,000). Masaaki Nagumo developed Land Walker on the basis of the dream he has had in his childhood that enables a person to go on. (Photo by Koichi Kamoshida/Getty Images)

Ten day old male Gorilla “Fataki” clings to his mother “Frala” during his media debut at Taronga Zoo June 4, 2003 in Sydney, Australia. Fataki was born on May 24, 2003 and was the fourth Gorilla to be born at Taronga Zoo since the opening of the Gorilla Forest in 1997. (Photo by Chris McGrath/Getty Images)

Decorative model Elephants stand in Trafalgar Square on May 4, 2010 in London, England. 260 of the decorative life size baby Elephants have been designed by established and emerging artists including Paul Smith, Marc Quinn and Julien Macdonald and have been placed across the capital in prominent places such as Buckingham Palace, Parliament Square and Trafalgar Square. (Photo by Dan Kitwood/Getty Images)

A five meters high sculpture “Pentateuque” created by Contemporary French artist Fabien Merelle, is displayed in Central, business district of Hong Kong, Tuesday, May 21, 2013. The artwork brings to real life the fantastical and seemingly impossible act of an average man balancing a gigantic elephant. The elephant and the man are modeled on one at the Singapore Zoo and on the artist himself. (Photo by Kin Cheung/AP Photo)

A model of a ghost made from translucent fibreglass is lit from inside at Gem's (Wax Models) Ltd, in the Portobello Road area of west London. The ghost is due to go to the Capistrano Mission Museum in California, where tourists are told the legend of how he frightened a young Indian girl novice to death. 1st May 1965. (Photo by Chris Ware/Keystone Features)