给定一段英文文本，生成其简要概述，并输出概述的前两句话。 
The Great Barrier Reef is the world's largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching for over 2,300 kilometers (1,400 mi) over an area of approximately 344,400 square kilometers (133,000 sq mi). The reef is located in the Coral Sea, off the coast of Queensland, Australia.
The Great Barrier Reef is the largest coral reef system on earth, spanning over 2,300 kilometers and covering approximately 344,400 square kilometers. It is situated in the Coral Sea, off the coast of Queensland, Australia.