The Largest Coral Reefs

The Great Barrier Reef

• Consisting of more than 3,000 reef systems and coral cays, the Great Barrier Reef is the largest reef on the planet. Situated off the coast of Australia, parallel to Queensland, the Great Barrier Reef is more than 1,800 miles long, and is up to 40 miles wide in some parts. Larger than the Great Wall of China, the Great Barrier Reef is the only living organism on the planet visible from space.

Apo Barrier Reef

• Apo Barrier Reef is the world's second-largest coral reef. Set off the coast of the Philippines, Apo Barrier Reef is 15 miles off the western coast of the Philippines' Mindoro Island. Measuring 21 miles long, the reef is divided into two lagoon systems that total 27,469 hectares.

Florida Keys Reef Tract

• The Florida Keys Reef Tract lies off the coast of the Florida Keys, extending from Stuart, Florida, on the Atlantic coast all the way to the Dry Tortugas in the Gulf of Mexico. The only living coral barrier reef in North America, the Florida Keys Reef Tract is the third-largest coral barrier reef in the world.

New Caledonia Barrief Reef

• Extending 930 miles, the New Caledonia Barrier Reef is the second-longest double barrier reef in the world. This reef is claimed by the French territory of New Caledonia in the South Pacific, and provides a home to a diverse group of marine life.

Mesoamerican Reef

• Located off the coast of Mexico's Yucatan Peninsula, the Mesoamerican Reef is almost 700 miles long, stretching from the northern tip of the peninsula to northern Honduras. The Mesoamerican reef is home to more than 65 different species of coral and 500-plus species of fish. This reef system is more than 225 million years old, and serves as a natural barrier to storms and hurricanes.