The second largest lake in the South American country of Bolivia has completely dried up.
Lake Poopo used to be about 1,000 square kilometres big but it's been shrinking for several years and in December it completely evaporated.
It's bad news for wildlife, like fish and birds, who live in the area and depend on the lake for food.
More than 100 families have had to leave their homes in the last three years.
The lake has dried up before, and reappeared later on, but scientists have warned that recovery might not be possible this time.
No one knows for sure why the lake has disappeared, but repeated droughts caused by the El Nino weather phenomenon is thought to be an important factor.
Another reason could be that water from the rivers that feed into the lake has been diverted for mining and farming, meaning that less water reaches the lake itself.
Misuse of the water supply and a failure on the part of the Bolivian government to act on existing management plans are partly responsible for the rapid drying of the lake over the past few years, says Lisa Borre, a senior researcher with the Cary Institute for Ecosystem Studies in New York, who studies lake ecosystems.
"The lake was very shallow, only a few feet deep, and it is in an arid climate, so its level fluctuates a lot with the weather," Borre says, adding that Poopó has shrunk significantly a number of times in the past, "but it's never been this bad."
Some scientists have suggested that recovery may not be possible, although Borre thinks the basin is likely to fill again once rains return. Still, there are important lessons to be learned.
"The Bolivian government is blaming El Niño and climate change, and certainly those played a role, but they are not saying that they have also failed to implement the management plan for the basin," says Borre.