In this June 17, 2014 photo, a North Korean man takes shelter in the rain next to long propaganda billboards in the town of Samjiyon in North Korea's Ryanggang province. The Associated Press was granted to embark on a weeklong road trip across North Korea to the country’s spiritual summit Mount Paektu. The trip was on North Korea's terms. An AP reporter and photographer couldn't interview ordinary people or wander off course, and government “minders” accompanied them the entire way. (Photo by David Guttenfelder/AP Photo)

Students stand on the roof of a wooden boat as haze blankets the Musi River while they travel to school in Palembang, on Indonesia's Sumatra island, September 10, 2015. Indonesia is investigating 10 firms over worsening forest fires that have created a blanket of smog over Southeast Asia, threatening them with sanctions if they are found responsible, a government minister said on Tuesday. The thick haze from Indonesia's Sumatra and Kalimantan islands has forced the repeated cancellation of flights in the area and pushed air quality to unhealthy levels in neighbouring Singapore and Malaysia. (Photo by Reuters/Beawiharta)

The Luminous Lantern Parade on June 10, 2016 in Brisbane, Australia. The Luminous Lantern Parade was held at Brisbane’s South Bank on Friday, featuring a parade of glowing animals and characters of all shapes and sizes lighting up the night sky. (Photo by Glenn Hunt/Getty Images)

British Holidaymakers seen partying partying in Punta Bella main Street in Magaluf, a major holiday resort on the Spanish island of Majorca this summer, July 2017. (Photo by Splash News and Pictures)

Nuns from the United States dance as they wait for the Holy Mass with Pope Francis (not seen) at the Campus Misericordiae in Brzegi, Poland, 31 July 2016. Today Pope Francis will celebrate the holy mass ending the World Youth Day 2016 in Poland. (Photo by Marcin Obara/EPA)

A Perseid meteor streaks across the sky above Inspiration Point early on August 12, 2016 in Bryce Canyon National Park, Utah. The annual display, known as the Perseid shower because the meteors appear to radiate from the constellation Perseus in the northeastern sky, is a result of Earth's orbit passing through debris from the comet Swift-Tuttle. (Photo by Ethan Miller/Getty Images)

Early morning storms over the Masai Mara National Reserve, Kenya on August 26, 2016. (Photo by Action Press/Rex Features/Shutterstock)

Singers “Elle & The Pocket Belles” attend day 3 “Ladies Day” of the Qatar Goodwood Festival on August 3, 2017 in Chichester, England. (Photo by David Hartley/PA Wire)