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)

City workers transport a load of sandbags to be used in re-enforcing a levee gate past the Yazoo & Mississippi Valley Railroad Station May 11, 2011 in Vicksburg, Mississippi. The Mississippi river at Vicksburg is expected to crest at a record 58.5 feet. Heavy rains have left the ground saturated, rivers swollen, and have caused widespread flooding in Missouri, Illinois, Kentucky, Tennessee, and Arkansas. (Photo by Scott Olson/Getty Images)

Actress Rosario Dawson (“Men in Black II”, “25th Hour”, “Sin City”, “Death Proof”, “Eagle Eye”, “Alexander”, “Percy Jackson and the Olympians”) walks the runway at the Fashion For Relief at Forville market during the 64th Annual Cannes Film Festival on May 16, 2011 in Cannes, France. (Photo by Ian Gavan/Getty Images)

BMX biker and event compere Ben Manuel warms up for the annual Hub Festival May 20, 2011 in Liverpool, England. This weekend's annual hub festival is an urban mix of art, music and action sports staged at Otterspool Promenade and attracts the top BMX, Skateboarders, artists and musical talent from across the UK. (Photo by Christopher Furlong/Getty Images)