For thousands of years, the conditions that created the world's largest living thing have been in perfect balance. Even the elements here work in harmony to build the reef. Situated in the tropics, the sun hits the water at an angle so precise that almost no heat is reflected, but is absorbed into the warm, fertile waters.

 

But not everything here is so benign. Some of nature's most brutal forces rage in this sea. From the west, cyclones gather strength as they race across the Pacific. But the reef has found a way of protecting itself. It's called the Great Barrier for a reason. It acts as a wave break, soaking up the power of storms and sheltering the coastline.

 

It's Australia's first line of defense against the rages of the ocean, protecting not just the reef, but an entire continent. But how does something so fragile survive this onslaught? In fact, it doesn't just survive. Miraculously, it thrives.

 

The waves here act like forest fires, sweeping through the reef, clearing away old growth. Dead and dying coral is removed, and space is made for new life to take hold. And wave action carries off sand and silt that could smother the corals.