You might remember the article about the red rocks that puzzled scientists for a long time.
This week, scientists and citizens were stunned to see how the Azov Sea suddenly turned red.
“It might be a sign of the coming events, or even end of the world” say the locals.
The officials have been trying to calm down people, explaining that although this does not happen often it is a natural phenomenon that does sometimes occur.
Azov Sea, or Sea of Azov as it is often called is situated off the southern shores of Ukraine and Russia.
It forms a northern extension of the Black Sea, to which it is linked on the south by the Kerch Strait. The Sea of Azov is about 210 miles (340 km) long and 85 miles (135 km) wide and has an area of about 14,500 square miles (37,600 square km).
Scientists have discovered about 600 species of planktonic algae in the Sea of Azov.
The number of species is dominated by diatoms and green algae; blue-green algae and pyrophites are significant, and euglena and yellow-green algae form only 5% of the species.
It is still unclear what happened. The change of color could be due toxic pollution, but most likely the reason for bloody red color of the sea is algal blooms that are not dangerous to humans.