As the sun rises over the blue waters off Sri Lanka’s southern coast, the largest mammal on earth breaks the surface. Beneath these waves lives a unique population of pygmy blue whales which feed, mate and play closer to shore in greater numbers than any other blue whale population on the planet. But the key to their existence lies hundreds of miles inland, at the top of Sri Lanka’s highest mountains. As the monsoon rains pour onto land, over a hundred rivers flow from the mountains, carrying with them nutrients which flood into the seas. From tangled mangrove forests to pristine white-sand beaches, Sri Lanka’s coastal waters present a show of nature’s most magnificent marine mammals. As turtles lay their eggs on palm-fringed shores, Sri Lanka’s iconic stilt fishermen wait for the shoals of herring and mackerel which the changing seasons bring. And out at sea, thriving coral reefs hide ancient wrecks filled with fish, while hundreds of dolphin race among the waves. This is an oceanic island where water, above all things, rules.