Mud-covered tourists pretend to be trapped inside a mud prison at the Daecheon Beach Mud Plaza in the city of Boryeong on South Korea's west coast, July 17, as they take part in the Boryeong Mud Festival, which opened that day and runs through July 26. Boryeong mud is rich in natural mineral component and is considered to prevent skin aging. (Photo by EPA/Yonhap)

An Indian boy dressed as Hindu god Shiva to attract alms from devotees chats with tourists as they sit on benches partially submerged in flood waters on the banks of the River Ganges in Allahabad, India, Thursday, July 30, 2015. The Ganges, one of India's largest rivers is flooded following monsoon rains. (Photo by Rajesh Kumar Singh/AP Photo)

Labourers carry a basket packed with vegetables through a wholesale market in Kolkata, India, February 26, 2016. (Photo by Rupak De Chowdhuri/Reuters)

An abandoned tank left by Boko Haram, February 20, 2016, seen on the road to Michika, Nigeria – a town formerly occupied by the insurgents. On April 14, 2014, 300 schoolgirls in the Chibok village in Nigeria were kidnapped by the terrorist group, Boko Haram. Two years later, the majority of these girls are still missing. According to the Global Terrorism Index Report 2015, Boko Haram, which operates mainly in Nigeria, has become the most deadly terrorist group in the world. (Photo by Danielle Villasana)

Boys play with water as they celebrate Myanmar's New Year Water Festival of Thingyan in Yangon, April 13, 2016. (Photo by Soe Zeya Tun/Reuters)

Relatives and friends react during the funeral of Bryan Sandoval, 17, a victim of a landslide that has left at least 112 dead and 350 missing people, in El Cambray II village, Santa Catarina Pinula, Guatemala, 04 October 2015. The landslide took place on 01 October 2015 when heavy rains saturated the soil. (Photo by Esteban Biba/EPA)

A Great White Pelicans eats fish in the Mishmar HaSharon reservoir, Israel, Wednesday, November 4, 2015. Thousands of Pelicans stop in the reservoir for food provided by the Israeli nature reserves authority as they make their way to Africa. (Photo by Ariel Schalit/AP Photo)

A man drinks at a "colored" water cooler in a streetcar terminal in Oklahoma City, July 1939. (Photo by Reuters/Library of Congress)