Ethiopian Orthodox worshippers celebrate the Holy Fire ceremony at the Ethiopian section of the Church of the Holy Sepulcher on April 23, 2011 in Jerusalem's Old City, Israel. Hundreds of Orthodox Christians, all from different sects, participated in the ceremony a day preceding Orthodox Easter, and has been celebrated by worshipers for the last 1,200 years. (Photo by Uriel Sinai/Getty Images)

President Barack Obama speaks to the press in the Briefing Room of the White House April 27, 2011 in Washington, DC. US President Barack Obama released a long form version of his birth certificate after extended criticism by those who do not believe he was born in the United States. (Photo by Brendan Smialowski/Getty Images)

In this handout image provided by the City of New York, a Nissan NV200 is seen as a New York City taxi cab in New York City. The Taxi and Limousine Commission along with New York City Mayor Michael Bloomberg announced the Nissan NV200 designed by Nissan North America, Inc., has been chosen as the winner of the Taxi of Tomorrow competition and will become the City's exclusive taxicab for a decade. (Photo by City of New York via Getty Images)

A group of San Bushmen from the Khomani San community practice their hunter-gatherer craft in the Southern Kalahari desert on October 15, 2009 in the Kalahari, South Africa. One of the largest studies of African genetics by an international team from the University of Pennsylvania, published in April 2009, revealed that the San of Southern Africa are the most genetically diverse on earth, and that the San homeland could be the spot where modern humanity began. (Photo by Dan Kitwood/Getty Images)

Bonhams expert Michaela Vergottis holds a yellow Jade Chinese Imperial Sceptre on May 9, 2011 in London, England. The piece which is thought to have been taken by British Troups during the Boxer Rebellion is expected to fetch between £800,000 – 1.2 M GBP when it goes on sale at the “Chinese Art” sale at Bonham's auction house on May 12, 2011. (Photo by Dan Kitwood/Getty Images)

A newly-born male baby elephant, who so far does not have a name, walks with his mother Temi during his first venture outside at their enclosure at the Tierpark Hellabrun zoo on May 12, 2011 in Munich, Germany. The baby elephant was born at the zoo on May 6. (Photo by Alexander Hassenstein/Getty Images)

The X-47B prototype on Tuesday flew off an aircraft carrier and into the history books. Today's achievement, the first-ever catapult launch of an unmanned aircraft from the flight deck of a carrier, promises to open up a new chapter in the annals of naval aviation. Photo: An X-47B pilot-less drone combat aircraft is launched for the first time off an aircraft carrier, the USS George H. W. Bush, in the Atlantic Ocean off the coast of Virginia, May 14, 2013. The U.S. Navy made aviation history on Tuesday by catapulting an unmanned jet off an aircraft carrier for the first time, testing a long-range, stealthy, bat-winged plane that represents a jump forward in drone technology. (Photo by Jason Reed/Reuters)

Beautiful, strange and occasionally alarming pictures from the shortlist for this year’s Wellcome image awards – which celebrate the very best in science photography and imaging – from an x-ray of a bat to a micrograph of a kidney stone. The exhibition opens on 12 March at three science centres and the Museum of Science and Industry in Manchester. Photo: Scanning electron micrograph (SEM) of an Arabidopsis thaliana flower, also commonly known as thale cress. Some of the anthers are open, revealing pollen grains ready for dispersal. Arabidopsis was the first plant to have its entire genome sequenced and is widely used as a model organism in molecular and plant biology. Horizontal width of image is 1200 microns. Magnification 100x. (Photo by Stefan Eberhard/Wellcome Images)