STORY: Santiago's Mapocho used to be a "dead river".
It had no vegetation, was filled with garbage -- and even had a foul smell.
But now -- birds, fish, and flowers are finally returning to the river that cuts through Chile's capital.
So how did it go from a contaminated eyesore -- to a thriving urban wetland?
The transformation didn't happen overnight.
It's the result of a decade-long effort between the regional government - and nearby communities.
They wanted to revive the river's biodiversity and turn it into an 11-mile-long protected park.
Joaquin Moure is the director of the Mapocho Vivo foundation, helping to protect the river.
He says it's taken species ten years to recuperate after a local water supply company diverted wastewater to treatment plants -- that was once destined for the river.
"It's been 10 years that wastewater outlets don't go into the river, 10 years of clean water flowing. And that's why species like Andean catfish and freshwater crabs are returning to the river. We have even seen coypus and yellow-billed pintails nesting in the most urban parts of the river.”
According to Mauricio Fabry, head of the regional government's environmental office -- the river even acts as a "carbon sink" -- lowering the city's temperature by up to 2 degrees Celsius, or about three-and-a-half degrees Fahrenheit -- and helping to control invasive species.
He says the next step - will be to give the river an official 'urban wetland' designation -- which will make it easier to give it legal protections.
It'll help prevent disruptive activities -- like dumping, sand and rock extraction, and real estate development.