Final match Soccer Humanoid Kid Size between DARwIn vs. AUTMan at the World Championship finals of RoboCup 2013 in Eindhoven (NL). (Photo by Bart van Overbeeke)

Festivalgoers watch two actors of the Wasteland Warriors movement fight in a cage at the world's largest heavy metal festival, the Wacken Open Air 2019, in Wacken, Germany on August 3, 2019. Wacken is a village in northern Germany with a population of 1,800 that has hosted the annual festival, which attracts heavy metal fans from around the world, since 1990. (Photo by Wolfgang Rattay/Reuters)

A municipal worker sits on a bench, next to a statue, in Nizhny Novgorod, Russia, during the 2018 soccer World Cup, Thursday, June 28, 2018. Nizhny Novgorod was a “closed city” during the Soviet era. It was known as Gorky until 1990 and it was here that dissident scientist Andrei Sakharov was held under house arrest. Now the city hosts six World Cup matches and is teeming with tourists. That was unthinkable in the Soviet era and even rare now in a city that is seldom visited by outsiders. (Photo by Vadim Ghirda/AP Photo)

Tourists are visiting Pingyao Ancient City in Shanxi Province, China, on July 9, 2024. (Photo by Costfoto/NurPhoto/Rex Features/Shutterstock)

Revellers participate in the annual gay pride parade in Amsterdam, Netherlands on August 4, 2018. (Photo by Piroschka van de Wouw/Reuters)

Przemek Pawlicki performs during training in Leszno, Poland on May 12, 2016. A stunning action-packed catalogue of photographs from sporting events around the world has been released by Red Bull. The energy drink giant's photographers have been busy capturing extraordinary images of action sports and some of the world's greatest daredevils. (Photo by Lukasz Nazdraczew/Red Bull/SWNS.com)

A handout picture provided by Solar Impulse on 18 March 2015 shows the Swiss solar-powered plane Solar Impulse 2, HB-SIB, taking off with Swiss explorer Andre Borshberg on board for the third leg Ahmedabad to Varanasi, of the Round-The-World, in Ahmedabad, India, 18 March 2015. Swiss explorers Bertrand Piccard and Andre Borschberg attempt to circumnavigate the world flying with an aircraft, with a 72 metres wingspan, powered only by solar energy without a drop of fuel. (Photo by EPA/Solar Impulse)

Among the fish populations that could be harmed by the Xayaburi dam in Laos is the critically endangered Mekong giant catfish, considered by the Guinness Book of World Records to be the world’s largest freshwater fish. The fish, which grows to 650 pounds and about 10 feet long, is only found in the Mekong River. It is migratory, moving between downstream habitats in Cambodia upstream to northern Thailand and Laos each year to spawn. Some experts fear the Xayaburi dam could block the migration and drive the giant catfish to extinction. (Photo by Courtesy of Zeb Hogan/University of Nevada, Reno)