Opposition students march against Venezuelan President Nicolas Maduro's government in Caracas February 12, 2015. Venezuelan troops blocked students during marches against Maduro on Thursday as pro-government supporters also rallied on the anniversary of 2014 protests that led to 43 deaths. In Caracas, troops cordoned off scores of students on an unauthorized march to a church where they planned a mass in honour of demonstrators who died. (Photo by Jorge Silva/Reuters)

A group of women dance in a pool in Callao, Peru, Sunday, February 22, 2015. One of centers for the front-doorstep, pool-party phenomenon is Lima's port city of Callao. People hold parties in them and sometimes entire blocks chip in to buy a pool, which can be had in local department stores for a bit over $100. (Photo by Martin Mejia/AP Photo)

A child watching the sea while residents try to clear the bed of a river that has been blocked by debris left by Hurricane Matthew, in the commune of Roche-a-Bateaux, in the south west of Haiti, on October 21, 2016. At least 546 people were killed and more than 175,000 people lost their homes when Hurricane Matthew roared ashore on October 4, packing winds of 145 miles (230 kilometers) per hour. (Photo by Hector Retamal/AFP Photo)

A body laying in the street is covered as police block the area around the site of a shooting in Halle an der Saale, eastern Germany, on October 9, 2019. At least two people were killed in a shooting on a street in the German city of Halle, police said, adding that the perpetrators were on the run. “Early indications show that two people were killed in Halle. Several shots were fired. The suspected perpetrators fled in a car”, said police on Twitter, urging residents in the area to stay indoors. (Photo by Sebastian Willnow/dpa/AFP Photo)

A woman holding a girl walks as police officers block the street during a rally called by the opposition leader Raila Odinga who claims the last Kenyan presidential election was stolen from him and blames the government for the hike of living costs in Kibera, Nairobi on March 27, 2023. Police fired tear gas to disperse anti-government protests on March 27, 2023 over the high cost of living, after the opposition vowed demonstrations would go ahead despite a police ban. (Photo by Yasuyoshi Chiba/AFP Photo)

Aerial view huge cliff rockfall at East Cliff at West Bay in Dorset, UK which happened overnight and has blocked the beach below on December 30, 2024. Golfers can be seen playing on the 15th green at Bridport & West Dorset Golf Club which is next to the latest landslip. The cliff has had frequent rockfalls in the past year which forced Dorset Council at the beginning of 2024 to close the South West Coast Path which runs along the top of the cliff due to safety concerns. (Photo by Graham Hunt/BNPS)

Wounded Reuters photographer Gleb Garanich, who was injured by riot police, takes pictures as riot police block protesters during a scuffle at a demonstration in support of EU integration at Independence Square in Kiev November 30, 2013. Riot police in the Ukrainian capital Kiev used batons and stun grenades to disperse hundreds of pro-Europe protesters from the city's main Independence Square early on Saturday, witnesses said. (Photo by Reuters/Stringer)

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)