Looking back on the Earth from space, mankind is able to see the impact humanity has made on Nature itself. But few wonders of man are as impressive as the Great Barrier Reef, a wonder made by Nature alone. The incredible biodiversity of this natural creation is a thing to behold.

Out of all the things that Nature and man have made, the Great Barrier Reef is the only collection of living 'things' that can be seen from space. While the Prairies and grasslands and forests are visible, they are not a true collective, like this amazing reef is. Working together, the corals coexist to sustain their existence and grow, making them a marvel of Nature.

A reef is a colony of corals that have built upon the hard skeletons left behind by their predecessors. Living coral has a bony exoskeleton itself, but by building on the 'bones' or shells of those who have come before, it grows. Corals in the Great Barrier Reef might have dome shapes to their colonies, might have branches like trees or might just be a multitude of small tubes coming together to form a different shape. Growing larger at a rate of one point three centimeters may not seem like a lot but to a coral colony, it's a good growth rate.

Individual coral colony members are called polyps, and are made up of a clear body that usually harbors algae. That's where most coral gets its colour from. Coral polyps are related to sea anemones and jellyfish. By giving the algae a safe home in shallow water, the algae is able to turn sunlight into sugars that can be used by the coral for energy. The interdependency of these species on the Great Barrier Reef is just one of the things that makes this natural wonder so special.

Other creatures also call the Great Barrier Reef home, such as thirty species of whales, dolphins and porpoises. Dwarf minke whales and more rare humpback whales roam the bottomless-seeming edges of the reef, while sea turtles and dugongs stick to the shallower water and feed on the many beds of sea grass. Salt water crocodiles prey on the many exotic fish found in the shallows, and live in the salty marsh habitats of the mangroves along the coast.

As humans take greater interest in the world and how it is put together, the value of natural wonders like the Great Barrier Reef become more obvious. Not only is it a hot tourist destination ideal for scuba diving and snorkeling, the reef also contributes to the temperatures of oceans near and far. Many of the species of animals that live in the reef can't be found anywhere else. This beautiful eco-system is being kept safe by the many cities around it that rely on it for tourism and fishing. And there are still many great spots for people to experience the reef up close and personal, making it one of the most popular places to go on vacation.