“El rio mas bonito del Mundo”, the most beautiful river of the world, the “River of five colors”, the “Rainbow River”, or even the “Escaped from Paradise”, are the shimmering appellations that Colombians give to Cano Cristales, a small stream located in the heart of the Macarena National Park, 150 km (93 miles) south of Bogota. Photo: A waterfall is seen at the end of the rainy season, in August, when the water level finally decreases, in the Cano Cristales RIver in the Sierra de la Macarena in Colombia. It has become covered with a bright pink endemic aquatic plant, Macarenia Clavigera. (Photo by Olivier Grunewald)

View of the “Sunset Lake” hot spring with it's unique colors caused by brown, orange and yellow algae-like bacteria called Thermophiles, that thrive in the cooling water turning the vivid aqua-blues to a murkier greenish brown, in the Yellowstone National Park, Wyoming on June 1, 2011. Yellowstone National Park, was established by the U.S. Congress and signed into law by President Grant on March 1, 1872. The park is located primarily in the U.S. state of Wyoming, though it also extends into Montana and Idaho and was the first national park in the world. It is known for its wildlife and its many geothermal features, especially the Old Faithful Geyser. (Photo by Mark Ralston/AFP Photo)

A instructor (2nd L) from the Philippine Mermaid Swimming Academy assists participants of a monofin swimming summer workshop as they practise floating in the water of a private pool in Paranaque city, metro Manila April 5, 2014. The Philippine Mermaid Swimming Academy workshops, which were originally conducted on the beaches of Boracay Island, central Philippines, currently cost 1,800 pesos per person ($40) for a two-hour session. (Photo by Romeo Ranoco/Reuters)

“Echus Chasma is a chasma in the Lunae Planum high plateau north of the Valles Marineris canyon system of Mars. Clay has been found in Echus Chasma that means that water once sat there for a time. Echus Chasma is approximately 100 km long and 10 km wide, with valleys ranging in depth from around 1 km to 4 km”. – Wikipedia

Photo: In this handout image supplied by the European Space Agency (ESA) on July 16, 2008, The Echus Chasma, one of the largest water source regions on Mars, is pictured from ESA's Mars Express. The data was acquired on September 25, 2005. The dark material shows a network of light-coloured, incised valleys that look similar to drainage networks known on Earth. It is still debated whether the valleys originate from precipitation, groundwater springs or liquid or magma flows on the surface. (Photo by ESA via Getty Images)

A competitor shouts as he takes part in the “Tough Guy” adventure race near Wolverhampton, central England, on January 29, 2017. The Tough Guy event, which is being held for the final time in its 30th year, challenges thousands of competitors to run a gruelling course whilst negotiating over 200 obstacles including: water, fire, and tunnels. (Photo by Oli Scarff/AFP Photo)

This watering hole is the social hub of the veldt; the scrubby grasslands that stretch across Namibia. The scorched earth supports sometimes fragile populations of magnificent wildlife – from endangered predators to plentiful herds of game. But these gentle giraffes and elephants need to be careful: lions don’t sleep at night, they hunt! The spectacular starscape above southern Africa is unchanged since explorers first mapped the continent. The photographer, Pietro Olivetta from Italy, said he had to be patient to capture these shots – but it was worth the wait. (Photo by Pietro Olivetta/Caters News)

In this Thursday, July 19, 2018, photo, a Syrian shopkeeper spraying water as waits for customers at the Hamadiyah market, named after the 34th Sultan of the Ottoman Empire Abdul Hamid II, in the Old City of Damascus, Syria. The celebratory mood in government-controlled areas stems from successive military advances in the past year and an impression that President Bashar Assad, with massive support by unwavering allies Russia and Iran, has won the war or at least militarily defeated the opposition trying to topple him. (Photo by Hassan Ammar/AP Photo)

In this November 30, 2017 photo, Douglas scoops up mud from the bottom of the polluted Guaire River, in search of gold and anything valuable he can sell, in Caracas, Venezuela. Some stretches of the river smell of sewer while others emit a toxic odor of fuel, a stench that stays in ones nose for hours after leaving the water. (Photo by Ariana Cubillos/AP Photo)