Emily Hasler, an English Heritage employee at Charles Darwin's home, Down House, cleans a rabbit bone in his old study on April 2, 2011 in Downe, England. Staff at the house are cleaning and preparing the property ahead of their peak visitor season. The house contains the study where Darwin wrote “On the Origin of Species”, as well as family rooms and an extensive garden that inspired the renowned scientist. (Photo by Oli Scarff/Getty Images)

A rebel fighter celebrates as his comrades fire a rocket barrage toward the positions of troops loyal to Libyan ruler Muammar Gaddafi April 14, 2011 west of Ajdabiyah, Libya. Rebels exchanged artillery and rocket fire with loyalist troops west of Ajdabiyah April 14 as the confict engulfing Libya continued. (Photo by Chris Hondros/Getty Images)

Plastinated human corpses posed to look like poker players stand on display at the Body Worlds exhibition on April 27, 2011 in Berlin, Germany. The exhibition, which features human and animal corpses plastinated by Gunther von Hagens, focuses on the role of the heart. It will be open to the public at the Postbahnhof from April 27 to August 14. (Photo by Sean Gallup/Getty Images)

David Beckham and Victoria Beckham arrive to attend the Royal Wedding of Prince William to Catherine Middleton at Westminster Abbey on April 29, 2011 in London, England. The marriage of the second in line to the British throne is to be led by the Archbishop of Canterbury and will be attended by 1900 guests, including foreign Royal family members and heads of state. Thousands of well-wishers from around the world have also flocked to London to witness the spectacle and pageantry of the Royal Wedding. (Photo by Pascal Le Segretain/Getty Images)

Decorated veterans take part in the Veterans Day parade in honor of the victory over the Nazi Germany, on May 11, 2011 in Jerusalem, Israel. Hundreds of Jewish World War II veterans from the Allied armies, mostly the former Soviet Union, and Israelis took part in the parade. (Photo by Avi Ohayon/GPO via Getty Images)

Models and designer Lindsay Degen (3rd from L) bare all at the latest DEGEN Spring 2012 presentation during Mercedes Benz Fashion Week at Artisanal House on September 7, 2011 in New York City. (Photo by Earl Gibson III/Getty Images)

A reveler waves a gay pride flag in front of the historic gay bar The Stonewall after the passing of a bill legalizing gay marriage in New York State on June 24, 2011 in New York City. New York State now joins Connecticut, Massachusetts, New Hampshire, Vermont, Iowa and Washington, D.C. in legally recognizing gay marriage. (Photo by Spencer Platt/Getty Images)

An officer is on fire as demonstrators clash with police during a protest against plans for new austerity measures on June 28, 2011 in Athens, Greece. Greece's largest labor unions have called for a 48-hour strike, while the Socialist government is beginning to push through legislation for cost cutting reforms. (Photo by Milos Bicanski/Getty Images)