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)

“The Daleks are a fictional extraterrestrial race of genetically manipulated mutants from the British science fiction television series Doctor Who. Various storylines portray them as having had every emotion removed except hate, leaving them with a desire to purge the Universe of all non-Dalek life. Collectively they are the greatest enemies of the series' protagonist, the Time Lord known as the Doctor. Their famous catchphrase is “Exterminate!”, with each syllable individually synthesised in a frantic electronic voice” – Wikipedia

Photo: Max Hardy, aged 6, stands by a street sign from the Doctor Who Experience as Dalek, from the cult television show Doctor Who watches him on April 16, 2011 in London, England. The Doctor Who Experience Exhibition is currently running at Kensington Olympia Two, celebrating the science fiction programme that was originally screened in 1963. (Photo by Matthew Lloyd/Getty Images for BBC Worldwide)

REUTLINGEN, GERMANY - NOVEMBER 17: Students hang out finished parchment leather at the LGR (Lederinstitut Gerberschule Reutlingen) tannery school on November 17, 2010 in Reutlingen, Germany. Even in early antiquity and up their hair or dried goat and sheep skins were used as material for documents. In the small Asian city Pergamon these skins were processed in large quantities for this purpose, so they formed the main trading arm of the city, of which the name is parchment is derived. In medieval times, reached the parchment is of great importance, it was such as France's production under the supervision of the University of Paris. Even now, important documents, placed on their unlimited shelf life as possible large value (eg diplomas, addresses, memory, writings, documents for primary and keystones) written on parchment...

A woman reacts as she uses a selfie stick to take a photo of herself at Tiananmen Square in Beijing, China, Thursday, April 30, 2015. Selfie sticks are gaining popular in China, and many people are using them at popular tourist destinations. (Photo by Andy Wong/AP Photo)

Dragon boat racers prepare for the fancy dress race on July 5, 2015 in Hong Kong, Hong Kong. The Hong Kong Dragon Boat Carnival will be staged from 3 July 2015 (Friday) to 5 July 2015 (Sunday). The carnival featured two key programmes: the CCB (Asia) Hong Kong International Dragon Boat Races in Victoria Harbour and the San Miguel BeerFest at the UC Centenary Garden in East Tsim Sha Tsui. (Photo by Taylor Weidman/Getty Images for Hong Kong Images)

A knight parades in the street during the traditional carnival parade in Cologne, western Germany, Monday, February 16, 2015. (Photo by Martin Meissner/AP Photo)

A frozen public bench is seen next to a lake side due to the heavy wind conditions in Geneva February 8, 2015. (Photo by Pierre Albouy/Reuters)

An Afghan man prepares tea for customers at a roadside tea shop on the outskirts of Jalalabad February 2, 2015. (Photo by Reuters/Parwiz)