See Photos of Chinese President Xi Jinping's State Visit to the United Kingdom

Chinese President Xi Jinping and his wife Peng Liyuan arrive for a four-day state visit at London's Heathrow Airport, on Oct. 19, 2015.

Prince Charles, Prince of Wales meets with President Xi Jinping at the Mandarin Oriental hotel in London, on Oct. 20, 2015

President Xi Jinping and Britain's Prince Philip, Duke of Edinburgh inspect the guard of honor on Horse Guards Parade in central London during the ceremonial welcome on the first official day of a state visit, on Oct. 20, 2015.

Queen Elizabeth II and President Xi, ride in the Diamond Jubilee State Coach along The Mall after the ceremonial welcome on Horse Guards Parade in London, on Oct. 20, 2015.

Queen Elizabeth and President Xi Jinping, are driven by carriage along The Mall to Buckingham Palace in London, Oct. 20, 2015.

Supporters of President Xi stand under a large Chinese flag before the President passes by on a horse-drawn carriage with Britain's Queen Elizabeth II on the Mall en route to Buckingham Palace in London, Oct. 20, 2015.

Queen Elizabeth II and President Xi arrive at Buckingham Palace in central London, on Oct. 20, 2015.

President Xi Jinping and First Lady Peng Liyuan with Queen Elizabeth II, and Prince Philip, Duke of Edinburgh view a display of Chinese items from the Royal Collection at Buckingham Palace in London, on Oct. 20, 2015

President, Xi addresses MPs and peers in Parliament's Royal Gallery in London, on Oct. 20, 2015.

President Xi Jinping and his wife Peng Liyuan accompany Britain's Queen Elizabeth II and her husband Prince Philip, Duke of Edinburgh, as they arrive for a state banquet at Buckingham Palace, in London, on Oct. 20,2015.

President Xi Jinping with Queen Elizabeth II at a state banquet at Buckingham Palace, in London, on Oct. 20, 2015.

Prime Minister David Cameron leaves The Plough pub with China's president Xi Jinping in Princes Risborough, England, on Oct. 22, 2015