Red lagoon
This lagoon situated in Huatalco, Mexico has turned blood red within the last 10 days. 
The reddish water of 'La Salina' lagoon impacts residents' life and kills wildlife in the area. 
After the mysterious overnight disappearance of a river near Veracruz, Mexico, it's now a lagoon that has unexpectedly turned color from green to red. 
Scientists believe the color is a result of a red tide, a phenomenon in which estuarine, marine, or fresh water algae accumulate rapidly in the water column, which changes the color of the surface water. 

The production of natural toxins and depletion of dissolved oxygen could be responsible for wildlife mortalities of marine and coastal species of fish, birds, marine mammals, and other organisms around the lagoon. 

Although red tides appear to be natural in some locations, residents believe that this algae blloom is the result of increased nutrient loading from human activities and low precipitation. Indeed, the 'La Salina' lagoon is known for being highly polluted and the sewage plant is not working properly. 

And there is the biblical explanation... Is the apocalypse near?