Staff of a boat restaurant on the Taedong River line up at the entrance as they wait to greet customers Sunday, June 18, 2017, in Pyongyang, North Korea. The boat is berthed along the river, which is the fifth longest river on the Korean Peninsula and runs through the country's capital, Pyongyang. (Photo by Wong Maye-E/AP Photo)

Woman on swings attached to a float during the Sexual Freedom Parade, part of Naughty in N'awlins held in New Orleans, Louisiana, Wednesday July 5th, 2017. These are the photos from inside the world’s largest swinging convention for couples. The exclusive images reveal the unlikely couples who like to engage in sexual relations with other people besides their partners – and show that swinging is more ‘normal’ than you think. (Photo by Mathew Growcoot/News Dog Media)

A common kingfisher sits on a branch of a tree after catching an insect in Allahabad, India, Sunday, July 9, 2017. The common kingfisher is a highly territorial bird that has to eat nearly sixty percent of its bodyweight every day. (Photo by Rajesh Kumar Singh/AP Photo)

A couple takes a selfie as Hoa Binh hydroelectric power plant opens the flood gates after a heavy rainfall caused by Talas typhoon in Hoa Binh province, outside Hanoi, Vietnam July 20, 2017. (Photo by Reuters/Kham)

Festival-goers take a bath in a mud pool during the 20th Boryeong Mud Festival on Daecheon beach in Boryeong City, some 190 kilometers west of Seoul, South Korea, 22 July 2017. Tourists flock to the area to experience the beneficial properties of the Boryeong mud, as well as for a variety of entertainment events. The festival runs from 21 until 30 July. (Photo by Jeon Heon-Kyun/EPA/EFE)

This Saturday, July 22, 2017 photo released by Tokyo Zoological Park Society, shows a giant panda cub at Ueno Zoo in Tokyo. The baby panda, born in June, got a check up on Saturday. (Photo by Tokyo Zoological Park Society via AP Photo)

Fans bath in the mud during the “Woodstock Festival Poland” on August 3, 2017 in Kostrzyn Nad Odra, Poland. The annual 3 day music festival organised by The Great Orchestra of Christmas Charity, one of Polands most respected charities aims at spreading awareness about drugs and violence. Przystanek Woodstock in Poland is the largest Europe open air festival. (Photo by Music/Alamy Stock Photo)

Performers dressed as Pikachu, a character from Pokemon series game titles, march during the Pikachu Outbreak event hosted by The Pokemon Co. on August 9, 2017 in Yokohama, Kanagawa, Japan. A total of 1, 500 Pikachus appear at the city's landmarks in the Minato Mirai area aiming to attract visitors and tourists to the city. The event will be held through until August 15. (Photo by Tomohiro Ohsumi/Getty Images)