Below its emerald waters, these tropical islands in the heart of the Pacific conceal the world's biggest underwater graveyard.

The easiest route is London to Frankfurt , Frankfurt to Tokyo (ANA; ana.com), Tokyo to Guam, and Guam to Chuuk (both United Airlines), which costs around £5,414 return.

“If you have a beach that was once, let’s say, mangroves and you clear it out, turn it into sand and plant some coconut palms, you’ve lost tons of structure, really complex, interwoven ...