This Thursday, April 30, 2015 photo shows Lebanese citizens walking on the Corniche, or waterfront promenade in Beirut, Lebanon. This photo was shot through the lowered veil of a niqab, which is worn by some conservative Muslim women. The cloth allows women to follow a strict interpretation of their religious beliefs by preventing others from seeing their faces. (Photo by Hassan Ammar/AP Photo)

A picture made available on 17 July 2015 shows the bright line of the Milky Way above the old oaks at the Rogalin landscape Park in Rogalin village, near Poznan, on the night of 16 July 2015. (Photo by Lukasz Ogrodowczyk/EPA)

The provincial highest chimney collapses as it is demolished by explosives in Shenyang, Liaoning province, April 28, 2014. The 150-metre-high chimney used to be part of a local heating factory, according to local media. (Photo by Sheng Li/Reuters)

Tourists play in front of a 3D painting on the wall of a house in Luoyuan village, Jinhua, Zhejiang province, August 26, 2015. The village hired a team to put on 3D paintings all over the valley as a method to attract tourists and improve the income of local villagers, according to local media. (Photo by Reuters/China Daily)

Couples kiss during a kissing contest in Wuhan, Hubei province, November 23, 2014. Some 20 couples attended the contest and the winners have been awarded an iPhone 6, according to local media. (Photo by Reuters/Stringer)

Pakistan girls make selfies holding a Pakistan-made weapon displayed at the four-day International Defence Exhibition and Seminar (IDEAS) 2016 in Karachi, Pakistan, Wednesday, November 23, 2016. (Photo by Shakil Adil/AP Photo)

In this August 21, 2017 photo released by the U.S. Defense Department, Qatari special operations personnel conduct a military free-fall Friendship Jump over Qatar. The U.S. military has halted some exercises with its Gulf Arab allies over the ongoing diplomatic crisis targeting Qatar, trying to use its influence to end the monthslong dispute, authorities told The Associated Press on Friday, October 6, 2017. (Photo by Staff Sgt. Trevor T. McBride/ U.S. Air Force via AP Photo)