A house built on a rock on the river Drina is seen near the western Serbian town of Bajina Basta, about 160km (99 miles) from the capital Belgrade May 22, 2013. The house was built in 1968 by a group of young men who decided that the rock on the river was an ideal place for a tiny shelter, according to the house's co-owner, who was among those involved in its construction. (Photo by Marko Djurica/Reuters)

This brave swimmer certainly has a brrracing workout each weekend she skinny dips in one of the coldest rivers in Europe which regularly plummets to temperaturess of –9C. Inna Vladimirskaya, 32, strips off on the banks of the Dnieper river, in Kiev, Ukraine, every Sunday morning, and takes a swim after jogging along the snowy banks of the river in the nip. (Photo by David Tesinsky/Caters News Agency)

Women perform yoga on a dried river bank in Yunyang county, Chongqing Municipality, August 21, 2016. (Photo by Reuters/China Daily)

A dog swims as a resident navigates his boat in a neighbourhood flooded by the Purus river, which continues to rise from days of heavy rainfall in the region, in Boca do Acre, Amazonas state March 14, 2015. According the state civil defense, more than 20,000 people have been left homeless along the Purus river, where incessant rains have flooded the area and caused the river to burst their banks. (Photo by Bruno Kelly/Reuters)

Beach Policeman, Potomac River, 1922. (Photo by National Photo Company/Colorized by Patty Allison)

A mahout splashes water on his elephant in the river Sabarmati on a hot summer day in Ahmedabad, India, May 20, 2015. (Photo by Amit Dave/Reuters)

In this photo taken on June 4, 2023, a man plunges into a river in Kishindeh district of Balkh province. (Photo by Wakil Kohsar/AFP Photo)

A member of the Fuerza Civil (Civil Force) police unit takes part in a simulated crime situation during a media presentation to show the police model that the federal government wants for the rest of the country, at the police academy in Monterrey December 17, 2014. Fuerza Civil, a tactical team of the police unit trained by the army, was created by the Nuevo Leon government in 2011 to curb down corruption and infiltration by drug gangs in the police corps, local media reported. Promising a new law to stop the infiltration of local governments by organized crime, President Enrique Pena Nieto pledged to reform the penal system and send an proposal to Congress to unify multi-layered police forces in Mexico's 31 states. (Photo by Daniel Becerril/Reuters)