Chinese soldiers leave after Chinese President Xi Jinping inspected troops of People's Liberation Army (PLA) Hong Kong Garrison at the Shek Kong Barracks in Hong Kong, Friday, June 30, 2017. Xi landed in Hong Kong Thursday to mark the 20th anniversary of Beijing taking control of the former British colony, accompanied by a formidable layer of security as authorities showed little patience for pro-democracy protests. (Photo by Kin Cheung/AP Photo)

A herd of elephants cross a road that passes through the flooded Kaziranga National Park in the northeastern state of Assam, India, July 12, 2017. (Photo by Anuwar Hazarika/Reuters)

Pupils of the Dao ethnic tribe return home from school along a hillside path at Suoi Thau village in Hoang Su Phi district of Vietnam's northern province of Ha Giang, located at the border with China, September 18, 2015. (Photo by Reuters/Kham)

Claudionor Jose de Deus, wearing a Santa Claus costume, arrives at Santa Rosa community to distribute presents to children, on the shores of the Amazon River in rural Manaus, Brazil, December 19, 2015. Jose de Deus is part of a volunteer group that distributes toys to children from poor neighborhoods and riverside communities that are distant from the city. (Photo by Bruno Kelly/Reuters)

In this November 21, 2015 photo, Camila Lopez Rivas, 14, poses for portraits on a beach in Havana, Cuba, as an assistant lifts the train of her dress to make it look like its flying in the wind. Camila lives in Miami, the daughter of a truck driver who left Cuba when she was a baby. She doesn't remember the island, but wanted to return for the photographs and videos that Latin American girls typically take for their 15th birthdays. (Photo by Ramon Espinosa/AP Photo)

A male deer barks at dawn during the annual deer rutting season at Richmond Park in London, Britain, October 9, 2016. (Photo by Toby Melville/Reuters)

Iranians flash the victory sign from their car while celebrating on a street in northern Tehran, Iran, Thursday, April 2, 2015, after Iran's nuclear agreement with world powers in Lausanne, Switzerland. The United States, Iran and five other world powers on Thursday announced an understanding outlining limits on Iran's nuclear program so it cannot lead to atomic weapons, directing negotiators toward achieving a comprehensive agreement within three months. (Photo by Ebrahim Noroozi/AP Photo)

March 28, 1967. Egg Roll; A large bunny attracted the attention of children and their parents during the annual Easter egg roll Monday on the south lawn of the White House. The bunny was made by Fred Johansen, Silver Spring, Md. Nearly 17,000 youngsters and adults took part in the egg rolling. The President and Mrs. John-son were not at the festivities because they were in Camp David, Md. The tradition of egg rolling was begun in 1878 during the administration of Rutherford B. Hayes. (Photo by Minneapolis Star Tribune)