Coral reefs are often called the rainforests of the sea, supporting around a quarter of all marine life despite covering less than one per cent of the ocean floor.
Yet over the past few decades, these vibrant underwater ecosystems have been devastated by climate change, coral bleaching, pollution, disease and destructive fishing practices.
While many scientists documented the decline, one diver from the Florida Keys decided to do something about it.
His name is Ken Nedimyer, and what began with a small coral nursery in his own backyard has grown into one of the world's most influential coral restoration movements.
Through simple but innovative techniques, thousands of volunteers and an expanding international network, Nedimyer has helped pioneer a practical way to restore damaged reefs and inspire communities to protect them.
