Students participate in a wet t-shirt contest at the MTV Beach Bash party put on by Global Groove at the Bahia Mar Hotel during the annual ritual of Spring Break March 26, 2008 on South Padre Island, Texas. The South Texas island is one of the top Spring Break destinations and attracts students from all over the country. (Photo by Rick Gershon/Getty Images)

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.

The vendors show the toy of snake at the Spring Festival Temple Fair for celebrating Chinese Lunar New Year of Snake at the Temple of Earth park on February 9, 2013 in Beijing, China. The Chinese Lunar New Year of Snake also known as the Spring Festival, which is based on the Lunisolar Chinese calendar, is celebrated from the first day of the first month of the lunar year and ends with Lantern Festival on the Fifteenth day. (Photo by Feng Li)

Boards stand lined up at the Rocinha Surf Association, ASR, headquarters at Rocinha slum in Rio de Janeiro, Brazil, Thursday, July 2, 2015. ASR has given free lessons to over 2,000 children from Rio's shantytowns in the hopes of keeping the boys, who are mostly in their early teens and a few girls occupied by the sport and off the streets. (Photo by Felipe Dana/AP Photo)

A boy runs as heavy rains and high waves brought by typhoon Linfa, locally named Egay, crash along a breakwater along Manila Bay at a slum area in Baseco, Tondo in Manila July 6, 2015. All shipping was ordered to remain in harbor and some flights were canceled in the northern Philippines, while schools were closed in the capital, Manila, on Monday due to flooding and landslides from a tropical storm, disaster officials said. Storm warnings were issued in at least 14 areas of the main Philippine island of Luzon as tropical storm Linfa moved slowly across the north of the Southeast Asian archipelago. It was carrying maximum wind gusts of 100 km per hour (60 mph). (Photo by Romeo Ranoco/Reuters)

A little boy shouts “Earthquake!” during a shouting contest, part of the annual evacuation drill on the National Disaster Prevention Day on September 1, 1986. The contest was aimed at teaching youngsters the importance of telling neighbors quickly and loudly of a disaster when it hits. The drill is annually conducted through out the country on the day marking the anniversary of the Great Kanto Earthquake that hit the Japanese capital and its vicinity on September 1, 1923, killing more than 104,000 people. (Photo by Sadayuki Mikami/AP Photo)

In this Friday, February 27, 2015 photo, an Israeli high-school senior preparing to join the Israeli military later this year participates in a privately run training camp for military combat fitness near Yakum, central Israel. With a mandatory three-year military service looming after graduation, teenage boys, and increasingly girls too, are gearing up for the draft, getting into shape and trying to improve their chances of acceptance into elite combat units. (Photo by Oded Balilty/AP Photo)

A Muslim Shi'ite boy carries a toy gun while standing next to a picture of Hezbollah leader Sayyed Hassan Nasrallah as he takes part in a march organised by Hezbollah during a re-enactment of the battle of Kerbala during a mourning process, ahead of the day of Ashura, in Saksakieh village, southern Lebanon, October 18, 2015. Ashoura, the most important day in the Shi'ite calendar, commemorates the death of Imam Hussein, grandson of the Prophet Mohammad, in the 7th century battle of Kerbala. (Photo by Ali Hashisho/Reuters)