Dancers from Xinjiang delegation perform during the Opening Ceremony for the 9th National Traditional Games of Ethnic Minorities of the People's Republic of China on September 10, 2011 in Guiyang, China. (Photo by Feng Li/Getty Images)

A man walks with a Cyberdog, produced by Chinese tech company Xiaomi, on February 19, 2022 in Beijing, China.The quadruped robots, often owned by tech and robotic enthusiasts, do not have a specific purpose so far, but the open source nature of the robots could make them suitable for several applications in the future. (Photo by Andrea Verdelli/Getty Images)

A man rides his horse next to Kosovo's coal-fired power plant near the town of Obilic on May 30, 2022. Two coal-fired power plants, Kosova A and Kosova B, are the main source of the alarming air pollution levels in Kosovo, and particularly in the town of Obilic, which is located between the two plants and near to their ash disposal sites and open-pit lignite mines. (Photo by Armend Nimani/AFP Photo)

With the entry of Poland into the European Union in 2004, Warsaw is currently experiencing the biggest economic boom of its history. The opening match of UEFA Euro 2012 is scheduled to take place in Warsaw. (Photo by: ryarwood; Source: Flickr)

An aerial view of open pits of CODELCO's Andina (L) and Anglo American's Los Bronces copper mines with Olivares glaciers in the background (top L) at Los Andes Mountain range, near Santiago city, November 17, 2014. The rock glaciers of the Chilean central zone, a huge source of water for the basins of the capital, are said to be threatened by the environmental impacts of hydroelectric and mining projects, according to environmental activists Greenpeace. (Photo by Ivan Alvarado/Reuters)

Military policemen try to open a path ahead for the funeral of 21-year-old Mohamed Adel, one of the army officers who died in yesterday's Sinai attacks, in Al-Kaliobeya, near Cairo, Egypt, July 2, 2015. Egypt launched air strikes on Islamist militant targets in the Sinai peninsula on Thursday, killing 23 fighters a day after the deadliest clashes in the region in years, security sources said. The sources said those killed had taken part in Wednesday's fighting in which 100 militants and 17 soldiers, including four officers, were killed, according to the army spokesman. (Photo by Mohamed Abd El Ghany/Reuters)

Police officers control the crowd (rear) while surrounding a man (front C) suspected to be involved in opening fire on a beachside hotel in Sousse, Tunisia, as a woman reacts (R), June 26, 2015. At least 27 people, including foreign tourists, were killed when at least one gunman opened fire on a Tunisian beachside hotel in the popular resort of Sousse on Friday, an interior ministry spokesman said. Police were still clearing the area around the Imperial Marhaba hotel and the body of one gunman lay at the scene with a Kalashnikov assault rifle after he was shot in an exchange of gunfire, a security source at the scene said. (Photo by Amine Ben Aziza/Reuters)

Jacob's Well is a perennial karstic spring in the Texas Hill Country flowing from the bed of Cypress Creek, located northwest of Wimberley, Texas. The twelve foot (four meter) diameter mouth of the spring serves as a popular swimming spot for the local land owners whose properties adjoin Cypress Creek. From the opening in the creek bed, Jacob's Well cave descends vertically for about thirty feet (ten meters), then continues downward at an angle through a series of silted chambers separated by narrow restrictions, finally reaching a depth of one hundred and twenty feet (forty meters). Until the modern era, the Trinity Aquifer-fed natural artesian spring gushed water from the mouth of the cave, with a measured flow in 1924 of one hundred and seventy gallons per second (six hundred and forty liters per second) discharging six feet (two meters) into the air. The spring is the greatest source of water recharging the Edwards Aquifer.