For all of the mysteries that remain about coral reefs, though, experts agree that climate change is an undisputed threat.

These sharks are critically endangered, and they are usually a solitary species, which makes the phenomenon even more unusual ...

For thousands of years, the people of Ulithi atoll have managed their reef atoll ecosystem using traditional knowledge. Wedged between Japan, the Philippines, and Papua New Guinea, they've used ...

There are three main types of coral reefs: fringing, barrier and atoll, the most common of which is the fringing reef. A fringing reef extends from the shore out into the ocean, forming a border along ...

A reef such as the one that encircles Île Europa ... but also to a million breeding pairs of seabirds. Bassas is an atoll that barely shows above the waterline and has a shark-filled lagoon ...

Before Charles Darwin came up with his famous theory about evolution, he proposed a theory of how coral reefs and atolls formed. Some of the specimens he collected to support his theory are now cared ...

This story appears in the September 2014 issue of National Geographic magazine. “If an alien had just one day on Earth and wanted to see a coral reef,” says National Geographic Explorer-in ...

If you start at Hawaii and travel 1,000 miles south, you’ll run into a cluster of tiny islands known as islets that make up ...