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)

Number 10. BELL H-13 SIOUX was a two-bladed, single engine, light helicopter built by Bell Helicopter. Westland Aircraft manufactured the Sioux under license for the British military as the Sioux AH.1 and HT. In 1947, the United States Air Force ordered the improved Bell Model 47A. Most were designated YR-13 and three winterized versions were designated YR-13A. The United States Army first ordered Bell 47s in 1948 under the designation H-13. These would later receive the name Sioux. The Bell-built H-13 B is seen airborne in this April 29, 1951 photo. The helicopter is equipped with a 173 horsepower engine, cruises at 85 miles per hour, climbs 900 feet in a minute and has a service ceiling of 11,500 feet. (Photo by AP Photo)

Ice Age – Tibet, China. “This is the Chinese version of the blue ice lake, Pumoungcuo, at an altitude of 5,070 metres (16,600 feet). This lake in Tibet freezes every winter. At night, under the low temperatures of -20C, you can listen to the sound of the ice cracking while capturing the most beautiful winter sky. The blue ice surface and dazzling Orion constellation create a fantasy landscape. I felt so happy to have the stars as my companion on this magical night”. (Photo by Daniel Zafra Portill/Milky Way Photographer of the Year)

In this Monday, July 25, 2016 photo, skydiver Luke Aikins smiles as he jumps from a helicopter during his training in Simi Valley, Calif. After months of training, this elite skydiver says he's ready to leave his chute in the plane when he bails out 25,000 feet above Simi Valley on Saturday. That's right, no parachute, no wingsuit and no fellow skydiver with an extra one to hand him in mid-air. (Photo by Jae C. Hong/AP Photo)

Exhilaration beyond imaginable, intense concentration on a single point, and complete freedom of soul – all these things very accurately describe the art of highlining. Highlining is a branch of a new sport called slacklining, which involves walking on special webbing secured between two points. Andi Lewis is one of the most famous slackliners in the world, particularly due to his performance during Superbowl Halftime Show in 2012. He never fails to surprise people with an amazing stunt or a project. This time he and his friends have created a completely incredible hand-knitted hammock located hundreds of feet above the ground. Just getting to this hammock requires immense skills and bravery. But once you’re finally there, you can rest a while, before mustering up the courage to go back across a narrow line with nothing but thin air beneath your feet.

An elephant mahout (trainer) lies on his elephant his feet resting on its ears as it rests and eats prior to opening day's play at the King's Cup Elephant Polo Tournament 2014 held near Bangkok, in Samut Prakan province, Thailand, 28 August 2014. The annual charity tournament runs until 31 August and involves 51 elephants who normally live on the streets and are used for begging. Sixteen competing elephant polo teams from 40 different nations take part in the charity event directed at raising funds to improve the lives of the elephants and elephant conservation in general. (Photo by Barbara Walton/EPA)

Roped up climbers leave the summit of Breithorn at 4,164 metres (13,661 feet) on the ridge marking the border with Switzerland (left) and Italy in the Alpine resort of Zermatt August 4, 2014. Switzerland will vote on November 30 on an initiative from the group Ecopop which proposes a cap on the number of immigrants. The group says it is motivated by concerns about a lack of living space exerting too much pressure on the land and natural resources, rather than by opposition to foreigners. (Photo by Denis Balibouse/Reuters)

An art installation formed with milk churns, made by land art artist Gerard Benoit a la Guillaume, is seen at the Chenau de Mayen in the resort of Leysin, Switzerland August 7, 2015. More than 80 milk churns were placed between the Tour d'Ai and the Tour de Mayen summits at an altitude of 2,000 meters (6,561 feet) above sea level under the direction of the artist, to be photographed for his ongoing art project entitled “Milk churns without borders”. (Photo by Denis Balibouse/Reuters)