A man waits for Queen Beatrix's abdication ceremony outside the Royal Palace in Amsterdam April 30, 2013. The Netherlands is celebrating Queen's Day on Tuesday, which will also mark the abdication of Queen Beatrix and the investiture of her eldest son Willem-Alexander. (Photo by Paul Vreeker/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.

Amateur contestants (L-R) Phil Bailey, John Hindle and Eren Emir pose in telephone booths during the annual European Elvis Tribute Artist Contest and Convention in Birmingham, central England January 2, 2015. (Photo by Darren Staples/Reuters)

A competitor reacts as she emerges from the water during the Tough Guy event in Perton, central England, January 26, 2014. The annual Tough Guy race – “the toughest race in the world” – at Perton in Staffordshire. Tough Guy claims to be the world’s most demanding one-day survival ordeal. First staged in 1987, the Tough Guy Challenge has been widely described as one of the hardest races of it’s type with up to one-third of the starters failing to finish in a typical year. (Photo by Darren Staples/Reuters)

A printed photograph taken on September 28, 2017 shows people bathing on the highway after Hurricane Maria destroyed people's homes, held up at the same spot of the highway where motorcyclists ride past in Naranjito, Puerto Rico, May 27, 2018. Thanks to the owners of the land alongside the highway, creek water was piped to the side of the road for people without water to use for bathing, washing clothes and dishes. (Photo by Ramon Espinosa/AP Photo)

A large stainless steel shovel lies on top of steamed crabs at the A.E. Phillips & Son Inc. crab picking house on Hooper's Island in Fishing Creek, Maryland August 26, 2015. Workers speed through the lump and back fin meat inside the crabs while leaving the more tedious task of picking the claws to others. (Photo by Jonathan Ernst/Reuters)

A Perseid meteor streaks across the sky over the community of Cold Creek on August 12, 2015 in the Spring Mountains National Recreation Area, Nevada. The annual display, known as the Perseid shower because the meteors appear to radiate from the constellation Perseus in the northeastern sky, is a result of Earth's orbit passing through debris from the comet Swift-Tuttle. (Photo by Ethan Miller/Getty Images)

Dancers from the School of American Ballet Chloe Ellis (R) and Amarra Hong (L) prepare for a performance at the Queens Theatre in the Queens borough of New York February 28, 2016. (Photo by Shannon Stapleton/Reuters)