There is a so called natural phenomenon that isn’t actually so natural to start with but here we go:
This happened in the coast of Sydney, a phenomenon not seen for more than three decades. All of the sudden the ocean becomes a huge foam wave that crashes into the shore.
Scientists explain that the foam is created by impurities in the ocean such as salts, chemicals, dead plants, decomposed fish and excretions from seaweed. All are mixed together by powerful currents which cause the water to form bubbles. The bubbles stick to each other and are carried towards the shore forming a big wave, the motion of the water causes the bubbles to swirl upwards and massed together they become foam!
It is quite an amazing thing to see, look at this picture:
Photo Source: dailymail.co.uk