'Coral bleaching is getting worse ... but the biggest problem is pollution'

Conservationists are battling to save the 700-mile Mesoamerican Barrier Reef in the Caribbean suffering the effects of mass tourism and global warming

• 'I have a lot of enemies': the Honduran marine park rangers facing death threats

The Mesoamerican Barrier Reef is the largest barrier reef in the western hemisphere - an underwater wilderness stretching over 700 miles along the coasts of Mexico, Belize, Guatemala and Honduras.

One of the most biodiverse ecosystems in the Americas, the reef is home to a dazzling variety of coral and more than 500 species of fish, and provides a livelihood for more than a million people. But now, a combination of mass tourism and poor waste management has left the reef increasingly vulnerable to climate change, placing this natural wonder in serious trouble.