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Britain's Prince Charles departs after delivering the keynote address on sustainable agriculture at Georgetown University, in Washington, on May 4, 2011.
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Prince Charles waiting to speak at "The Future of Food" at Georgetown University in Washington, May 4, 2011. The heir to the British throne resumed his public duties following his son Prince William and Kate Middleton's royal wedding last week, beginning with a three-day visit to the U.S. capital.
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Britain's Prince Charles of Wales, right, arrives to speak at "The Future of Food" conference at Georgetown University in Washington, May 4, 2011.
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Britain's Prince Charles points up at the rain as he arrives to speak at "The Future of Food" conference at Georgetown University in Washington, May 4, 2011.
(AP Photo/Alex Brandon
Britain's Prince Charles, left, shakes hands with Supreme Court Justice Stephen Breyer as he arrives at the Supreme Court in Washington, May 3, 2011.
AP Photo/Alex Brandon
Britain's Prince Charles, left, walks with U.S. Supreme Court Justice Stephen Breyer as he arrives at the Supreme Court in Washington, May 3, 2011.
AP Photo/Alex Brandon
Britain's Prince Charles, left, and Supreme Court Justice Stephen Breyer walk out of the Supreme Court in Washington, May 3, 2011.
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Britain's Prince Charles talks with local people who waited to meet him, as he leaves the Supreme Court in Washington, May 3, 2011.
AP Photo/Evan Vucci
Britain's Prince Charles smiles after he was given flowers by Pertula George, left, during a tour of the Common Good City Farm in Washington, May 3, 2011.
AP Photo/Jacquelyn Martin
Britain's Prince Charles, left, plants a tree with Nicole Pendergast, 7, and Kenan Dunson, both of Washington, during a visit to the Common Good City Farm in Washington, May 3, 2011.
AP Photo/Jacquelyn Marti
Britain's Prince Charles accepts flowers from Nicole Pendergast, 7, during a visit to the Common Good City Farm in Washington, May 3, 2011.
AP Photo/Jonathan Ernst
Wounded U.S. Marine Todd Nicely, left, shows his prosthetic hand to Britian's Prince Charles as Heather Nicely watches, at a reception for the British Forces Foundation and United Service Organizations (USO) at the British Embassy in Washington, May 3, 2011.
AP Photo/Jonathan Ernst
Britain's Prince Charles greets wounded U.S. Marine Matias Ferreira, right, before a reception for the British Forces Foundation and United Service Organizations (USO) at the British Embassy in Washington, May 3, 2011.
AP Photo/Jonathan Ernst
Britain's Prince Charles, right, greets Rep. Peter King, R-N.Y., left at a reception for the British Forces Foundation and United Service Organizations (USO) at the British Embassy in Washington, May 3, 2011.
AP Photo/Jonathan Ernst
Britain's Prince Charles applauds a musical performance as he sits beneath an Andy Warhol lithograph of his mother, Queen Elizabeth II, at a reception for the British Forces Foundation and United Service Organizations (USO) at the British Embassy in Washington, May 3, 2011.
AP Photo/Jonathan Ernst
Britain's Prince Charles, center, sits with the Chief of Staff of the U.S. Army Gen. Martin Dempsey and Chief of Staff of the U.S. Air Force Gen. Norton Schwartz, right, at a reception for the British Forces Foundation and United Service Organizations (USO) at the British Embassy in Washington, May 3, 2011.
