This next instalment is about coral reefs, which are so crowded that they play host to a perpetual battle for space, even among the coral itself. It starts life as a larva that becomes a polyp. Having multiplied, it hardens into a limestone skeleton and grows to form a reef. As the community flourishes, animals develop relationships with one another and such a place can feature a huge variety of ocean life.

Malaysian Borneo's beautiful coral reefs face environmental disaster as local fishermen resort to drastic, destructive fishing methods in order to survive, including using explosives or sodium cyanide