Visitors and a dog stand on the new “Skywalk” viewing platform on the Sonnenstein mountain in the Eichsfeld region near Bad Lauterberg im Harz, central Germany, on May 22, 2017. (Photo by Martin Schutt/AFP Photo/DPA)

A reveller takes part in the Gay Pride Parade in San Salvador, on June 24, 2017. (Photo by Marvin Recinos/AFP Photo)

This picture taken with an underwater camera shows Japan' s Yumi Adachi competing in the Mixed Duet technical final during the synchronised swimming competition at the 2017 FINA World Championships in Budapest, on July 17, 2017. (Photo by Bernadett Szabo/Reuters)

Men slide in the mud during the Boryeong Mud Festival at Daecheon Beach in Boryeong, South Korea, Saturday, July 22, 2017. The 20th annual mud festival features mud wrestling and mud sliding. (Photo by Ahn Young-joon/AP Photo)

In this January 7, 2016, photo, conservationists of Borneo Orangutan Survival Foundation hold a baby orangutan rescued along with its mother during a rescue and release operation for orangutans trapped in a swath of jungle in Sungai Mangkutub, Central Kalimantan, Indonesia. Last year's forest fires drove orangutans closer to the river bank, where they had to live in an over-populated swath of forest as thin as 30 meters wide along the river. (Photo by Dita Alangkara/AP Photo)

A Free Syrian Army fighter walks past a flag of al-Furqan brigade as a rifle hangs from a branch in the orchards of Kafar Zita in Hama countryside January 22, 2015. (Photo by Mohamad Bayoush/Reuters)

A Russian Sukhoi Su-25 fighter jet takes off during the withdrawal of Russian troops from Syria at Hmeymim airbase, Syria, March 16, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)

Workers hold an 80 Kg Paiche (Arapaima gigas) to return it to a pool at a breeding farm in Nueva Loja, Ecuador, March 25, 2016. (Photo by Guillermo Granja/Reuters)