An employee of the National Park Service takes a selfie with President Barack Obama, left, in the background meeting with the crowd after a tour of Everglades National Park on Earth Day, Wednesday, April 22, 2015, in Florida. Obama used the visit to warn of the damage that climate change is already inflicting on the nation's environmental treasures. (Photo by Lynne Sladky/AP Photo)

Labourers work at the installation site of Liquefied Petroleum Gas (LPG) pipeline on May Day or Labour Day in Chandigarh, India, May 1, 2015. (Photo by Ajay Verma/Reuters)

An instructor (C) adjusts the posture of students of flight attendant major during a training session at Anhui Foreign Languages University, in Hefei, Anhui province, China, May 25, 2015. (Photo by Reuters/China Daily)

Thai classical dancers perform for Phra Phrom, the Thai interpretation of the Hindu god Brahma, at the Erawan Shrine in Bangkok, Thailand, Friday, September 4, 2015. Thai authorities unveiled the restored centerpiece Friday of the Erawan Shrine, in the latest bid to restore confidence among Bangkok's tourism and business communities almost three weeks after a deadly bombing. (Photo by Sakchai Lalit/AP Photo)

Breitling Wingwalkers aircrafts perform during an aerobatic display at an air show in Zhengzhou, Henan province, China, September 25, 201. (Photo by Reuters/Stringer)

A man wearing a mask and dressed in a clown costume rides an electric tricycle while carrying a container in the shape of a rubber duck amid heavy smog in Beijing, China, December 29, 2015. (Photo by Jason Lee/Reuters)

A Nepalese mother applies make up to her daughter dressed as the living goddess Kumari as they wait for Kumari puja to start at Hanuman Dhoka temple, in Kathmandu, Nepal, Wednesday, September 14, 2016. Girls under the age of nine gathered for the Kumari puja, a tradition of worshiping young prepubescent girls as manifestations of the divine female energy. The ritual holds a strong religious significance in the Newar community that seeks divine blessings to save small girls from diseases and bad luck in the years to come. (Photo by Niranjan Shrestha/AP Photo)

Participants take pictures of themselves as others run past the Tiananmen gate during the Beijing Marathon in Beijing, China, September 17, 2016. (Photo by Damir Sagolj/Reuters)