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.

To commemorate the centennial of Britain’s involvement in the First World War, ceramic artist Paul Cummins and stage designer Tom Piper conceived of a staggering installation of ceramic poppies planted in the famous dry moat around the Tower of London. Titled “Blood Swept Lands and Seas of Red,” the final work will consist of 888,246 red ceramic flowers—each representing a British or Colonial military fatality—that flow through grounds around the tower.

Iguazu Falls are waterfalls of the Iguazu River on the border of the Brazilian state of Paraná and the Argentinian province of Misiones. The falls divide the river into the upper and lower Iguazu. The Iguazu River rises near the city of Curitiba. It flows through Brazil for most of its course. Below its confluence with the San Antonio River, the Iguazu River forms the boundary between Argentina and Brazil.

Migrants scramble aboard a train at the station in Beli Manastir, Croatia September 18, 2015. Migrant numbers in Europe will build up in coming days and their flows may fragment further into new routes, the U.N. refugee agency said on Friday, urging the European Union to grasp a last chance to resolve the refugee crisis next week. (Photo by Laszlo Balogh/Reuters)

Martin Rietze is a “volcano-chaser”, a particular breed of photographer who takes big risks for big shots. He was able to capture destructive and beautiful forces of nature at work on a trip to Japan in February 2013. His photos show the Sakurajima Volcano, an active volcanic who's record-breaking 1914 eruption sent lava flows across the island. (Photo by Martin Rietze/Guzelian)

Son doong cave is a cave in Phong Nha-Kẻ Bàng National Park, Bố Trạch district, Quảng Bình Province, Vietnam. Currently the biggest known cave in the world, the cave is located near the Laos-Vietnam border. Inside is a large, fast-flowing underground river.
In early August 2013, the first tourist group explored the cave on a guided tour at a cost of US$3,000 each. The group had six members from Australia, Norway, Russia and USA and spent 7 days and 6 nights for the tour. Next exploration trips will be arranged.

All throughout history of mankind people were fascinated by time, its flow, and how to measure it. Thus, the science of horology can into being, as people invented more and more sophisticated ways of measuring the passage of time. Truly, it’s one of the most profound characteristics of being a human, to feel and to ponder the meaning of time, its properties, and will we ever be able to move through it, not with it. Now, however, horology is mainly referred to the art of mechanical watchmaking. (Photo by MB&F)