Imagine a city built by animals, glowing in the sunlight, and bustling with life beneath the waves. That is a coral reef. During Coral Reef Awareness Week, we celebrate these remarkable ecosystems and the countless species that depend on them.

Coral reefs cover less than 1% of the ocean floor, yet they support roughly 25% of all marine life. What look like colorful rocks are actually colonies of tiny animals called coral polyps. Together, they build vast limestone structures that can last for thousands of years. The Great Barrier Reef is the largest living structure on Earth, stretching more than 1,400 miles along Australia's coast.

Reefs are full of surprises. Some corals glow thanks to fluorescent proteins that act like natural sunscreen, while parrotfish help create sandy beaches by turning coral into fine sand. For a glimpse of reef life at its richest, look to Raja Ampat in Indonesia, pictured here, where more than 75% of known coral species thrive. They may live underwater, but their impact reaches far beyond the shore.