Activists attend a parade to demand rights of gender equality to LGBT community members in Santiago, Chile, November 25, 2017. (Photo by Ivan Alvarado/Reuters)

A participant of the sled dogs race in action with the dogs in Stroehen (Lower Saxony), Germany, 18 October 2015. It is the first round of the North German Championship. (Photo by Peter Steffen/EPA)

A dancer lets a Russian tourist practice the traditional tannoura dance at a cafe in the Red Sea resort of Sharm el-Sheikh, Egypt November 10, 2015. The fallout from the crash of a Russian Metrojet passenger plane in Egypt's Sinai Peninsula could slash tourism income from Sharm al-Sheikh by half, the head of the region's travel agents' association said on Tuesday. Several airlines have suspended flights to the Red Sea resort since the Oct. 31 crash, which investigators and Western governments believe was likely to have been caused by a bomb. Thousands of Russian and British tourists have been flown home. (Photo by Asmaa Waguih/Reuters)

Ten-year-old Macy Friday, front left, reacts as she looks back at her family after meeting Hillary Clinton, front right, as she campaigns for U.S. Sen. Mark Udall, D-Colo., back, during a stop in the newly-renovated Union Station in Denver on Monday, October 13, 2014. Clinton appeared at an event to raise money for Udall's current re-election campaign and then headed to Las Vegas for another appearance on Monday night. (Photo by David Zalubowski/AP Photo)

Vanessa Silva, 38, feeds macaws that fly to her apartment window every day looking for food, in Caracas, Venezuela, on November 24, 2014. A group of gold-and-royal blue birds poked their heads through Silva’s window, as if saying “I’m here, is anyone home?” “I’d seen them flying when I was down on the street, and I thought ‘Oh how pretty,’” the 38-year-old said, a macaw eating out of her hand. (Photo by Ariana Cubillos/AP Photo)

Passengers climb to board an overcrowded train at a railway station in Dhaka August 8, 2013. Millions of residents in Dhaka are travelling home from the capital city to celebrate the Muslim Eid al-Fitr holiday, which marks the end of the Muslim holy fasting month of Ramadan. (Photo by Andrew Biraj/Reuters)

A girl jumps to touch cherry blossoms in full bloom in Fussa, outskirts Tokyo, Japan, 05 April 2014. Temperatures being very constant made blossoms to keep full bloom for holiday makers. (Photo by Kimimasa Mayama/EPA)

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)