Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge walk hand in hand from Buckingham Palace the day after their wedding to a waiting helicopter as they leave for a secret honeymoon location, on April 30, 2011 in London, England. The marriage of Prince William and Catherine Middleton was led by the Archbishop of Canterbury and was 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 John Stillwell - WPA Pool/Getty Images)

This undated image provided by World View shows World View capsule and balloon spacecraft that will rise to 100,000 feet above Earth for passengers to see the curvature of the planet and the blackness of space. Space tourism companies are employing designs including winged vehicles, vertical rockets with capsules and high-altitude balloons. While developers envision ultimately taking people to orbiting habitats, the moon or beyond, the immediate future involves short flights into or near the lowest reaches of space without going into orbit. (Photo by World View via AP Photo)

NYC morning fog. Wednsday, January 15, 2014, morning dense fog creates spectacular views over the East river of lower Manhattan, Brooklyn and Manhattan bridges as New Yorkers and tourist admire the scenery. View from Brooklyn Bridge Park in DUMBO Brooklyn. (Photo by Paul Martinka/New York Post)

Princess Charlene of Monaco and Prince Albert II of Monaco kiss on the balcony after the civil ceremony of the Royal Wedding of Prince Albert II of Monaco to Charlene Wittstock at the Prince's Palace on July 1, 2011 in Monaco. The ceremony took place in the Throne Room of the Prince's Palace of Monaco, followed by a religious ceremony to be conducted in the main courtyard of the Palace on July 2. With her marriage to the head of state of Principality of Monaco, Charlene Wittstock has/will become Princess consort of Monaco and gain the title, Princess Charlene of Monaco. Celebrations including concerts and firework displays are being held across several days, attended by a guest list of global celebrities and heads of state. (Photo by Pascal Le Segretain/Getty Images)

A general view of Hong Kong's business district is seen Thursday, August 1, 2013. (Photo by Vincent Yu/AP Photo)

Mature woman lying on bed, rear view. (Photo by Andersen Ross/Getty Images)

People view the sunrise scene at the Bund in Shanghai, east China, January 1, 2017. (Photo by Wang Hechun/Xinhua/Barcroft Images)

A bride weeps in a mass wedding ceremony at the CheongShim Peace World Center in Gapyeong, South Korea, Wednesday, February 12, 2014. Some 2,500 South Korean and foreign couples exchanged or reaffirmed marriage vows in the Unification Church's mass wedding arranged by Hak Ja Han Moon, wife of the late Rev. Sun Myung Moon, the controversial founder of the Unification Church. (Photo by Lee Jin-man/AP Photo)