The Great Barrier Reef

The Great Barrier Reef is the largest coral reef system in the world, comprised of over 2900 individual reefs that stretch over 2300 kilometers along the Queensland coast of Australia in the Coral Sea. It has been designated as a UNESCO World Heritage Site. The Great Barrier Reef is so large that it can be seen from outer space and is the largest structure on Earth made by living creatures.

Coral reefs are underwater ecosystems that are held together by calcium carbonate, which is secreted by corals. These are colonies that are basically the hardened exoskeleton of the coral.

Much of the Great Barrier Reef is protected by Australia's Great Barrier Reef Marine Park, which limits human activity, including tourism and fishing. However, the reef is threatened by the effects of climate change, including runoff into the ocean and has been greatly affected by coral bleaching, resulting in the loss of over half of its coral cover since 1985.

The Great Barrier Reef is one of the most ecologically diverse regions of the planet, including thirty species of whales, dolphins, and porpoises, six species of sea turtles, saltwater crocodiles, and 215 species of birds that either visit the reef or nest on the islands around the reef.