Green Bay Packers' Johnathan Calvin rides a bike to NFL football training camp on July 27, 2017, in Green Bay, Wis. (Photo by Morry Gash/AP Photo)

Rohingya refugee sisters Nur Kaida (R) and Ruhana hug each other at their shelter at the Palongkhali refugee camp near Cox's Bazar, Bangladesh December 21, 2017. (Photo by Marko Djurica/Reuters)

A Syrian youth Khaled from Raqqa walks on snow wearing slippers in the Bekaa Valley refugee camp in Lebanon after the first heavy snow storm hit Lebanon, January 3, 2016. (Photo by Jamal Saidi/Reuters)

Iraqi security forces take part in training, as they prepare to fight against militants of the Islamic State, at a training camp on the outskirts of Mosul January 10, 2015. (Photo by Azad Lashkari/Reuters)

An Iraqi girl, who fled from Falluja because of Islamic State violence, poses for a photographer at a refugee camp in Ameriyat Falluja, south of Falluja, Iraq, June 16, 2016. (Photo by Ahmed Saad/Reuters)

A woman talks to a man as two children play inside a wrecked car at a camp for displaced people in Port-au-Prince, Haiti, March 6, 2016. (Photo by Andres Martinez Casares/Reuters)

An internally displaced Afghan girl holds a child at a refugee camp in Kabul, Afghanistan May 31, 2016. (Photo by Mohammad Ismail/Reuters)

Yaks head towards the Everest base camp in Solukhumbu District April 28, 2014. (Photo by Navesh Chitrakar/Reuters)