An installation consisting of a series of bird boxes is displayed in a tree in Duncan Terrace Gardens in Islington on March 24, 2011 in London, England. The boxes by artists Bruce Gilchrist and Jo Joelson of “London Fieldworks”, were designed to reflect the architecture of the Georgian terraces and flats that surround the park in the community gardens. (Photo by Dan Kitwood/Getty Images)

The Tribute in Light is seen behind the Empire State Building on September 10, 2011 in New York City. The Tribute in Light is an art installation honoring those who perished in the 9/11 attacks. New York City and the nation are preparing for the tenth anniversary of the terrorist attacks on lower Manhattan which resulted in the deaths of 2,753 people at the World Trade Center. (Photo by Mario Tama/Getty Images)

Protesters dressed as cows march during a demonstration outside of the Wisconsin State Capitol on March 12, 2011 in Madison, Wisconsin. Tens of thousands of protestors staged a massive demonstration outside of the Wisconsin State Capitol one day after Gov. Scott Walker signed his controversial budget repair bill into law.

A clock showing a countdown to the start of the London 2012 Olympics is unveiled on March 14, 2011 in London, England. The clock is starting five hours from midnight when 6.6 million tickets for the Olympics will become available and 500 days before the Games start. There is a six-week window to apply for tickets on the London 2012 website.

A performer poses with “The Gronkle” and “Deadly Nadder” at the How to Train Your Dragon Media Call at Fox Studios on November 29, 2011 in Sydney, Australia. The “How to Train Your Dragon Arena Spectacular” world premiere will take place in Australia in March 2012. (Photo by Brendon Thorne/Getty Images)

The under-construction Shard building on December 5, 2011 in London, England. The 80 storey skyscraper will be Europe's tallest mixed-use building when it is completed in May 2012; it will contain offices, restaurants, residential apartments as well as a five star hotel. (Photo by Dan Kitwood/Getty Images)

Blood drips down from the face of a Shi'ite Muslim boy after practicing a self-flagellation ritual during a religious procession of the Ashura mourning period on December 6, 2011 in New Delhi, India. (Photo by Daniel Berehulak/Getty Images)

(L-R) Actors Simon Pegg, Paula Patton and Tom Cruise attend the “Mission:Impossible – Ghost Protocol” Germany Premiere at BMW Welt on December 9, 2011 in Munich, Germany. (Photo by Andreas Rentz/Getty Images for Paramount Pictures)