Spains Longest River At Spanish Stonehenge Turns Green

These images show how the waters of Spain's longest river have turned green around the ‘Spanish Stonehenge’ because of algae which are “threatening the ecosystem”.

The unexpected phenomenon happened in the waters of the Valdecanas Reservoir which is on the Tagus river in the province of Caceres in the autonomous community of Extremadura in south-western Spain.

The images were taken by the photographer Alberto Rubio from the municipality of Berrocalejo in the Dolmen of Guadalperal, dubbed in local media as the 'Spanish Stonehenge', a megalithic monument - dating back to from between 2000 and 3000 BC - which became visible a couple of months ago due to droughts in the Valdecanas Reservoir.