Ammunition airlift into besieged Khe Sanh, Operation Pegasus, April 1968. (Photo by Larry Burrows/AP Photo)

Reveller in costume with a broom jumps during a Zombie Walk event in central Kiev, Ukraine on October 27, 2018, ahead of Halloween celebrations on October 31. (Photo by Anatolii Stepanov/AFP Photo)

Mave Grace, 11, who had part of her arm chopped off by militiamen when they attacked the village of Tchee, stands with her sister Racahele-Ngabausi, aged two, in an Internally Displaced Camp in Bunia, Ituri province, eastern Democratic Republic of Congo, April 12, 2018. (Photo by Goran Tomasevic/Reuters)

Woman dons a mask a she prepares to dance in the streets during the feast of La Diablada, in Pillaro, Ecuador, Friday, January 4, 2019. The town of Pillaro kicks off the feast of the La Diablada with neighborhoods competing to bring as many people dressed as different characters. (Photo by Dolores Ochoa/AP Photo)

A woman yawns as she sits outside a hospital on a cold winter morning in Srinagar January 3, 2019. (Photo by Danish Ismail/Reuters)

Groundhog Club co-handler Al Dereume holds Punxsutawney Phil, the weather prognosticating groundhog, in front of the crowd gathered for the 133rd celebration of Groundhog Day on Gobbler's Knob in Punxsutawney, Pa. Saturday, February 2, 2019. Phil's handlers said that the groundhog has forecast an early spring. (Photo by Gene J. Puskar/AP Photo)

A musher handler with Alan Eischens team embraces one of Eischen's dogs just before the ceremonial start of the Iditarod Trail Sled Dog Race that begins a near 1,000-mile (1,600-km) journey through Alaska’s frigid wilderness in downtown Anchorage, Alaska March 5, 2016. (Photo by Nathaniel Wilder/Reuters)

In this Tuesday, December 20, 2016 photo, Mohammad Ramzan, right, reacts while talking to The Associated Press with his young bride Saima in Jampur, Pakistan. Saima was given as a bride to the older man by her father so he could marry the groom’s sister, a practice of exchanging girls that is entrenched in conservative regions of Pakistan. It even has its own name in Urdu: Watta Satta, “give and take”. A mix of interests – family obligations, desire for sons, a wish to hand off a girl to a husband – can lead to a young teen in an a marriage she never sought. (Photo by K.M. Chaudhry/AP Photo)