2 . John “Charlie” Veron-widely known as “the Godfather of Coral Reef (珊瑚礁)”-is a celebrated expert who has personally discovered nearly a quarter of the world’s coral species and has spent the past 45 years diving Australia’s Great Barrier Reef. But now the 73-year-old is raising the alarm about its future. The Great Barrier Reef, one of the natural wonders, is 2, 300 kilometers long and is the only living organism that can be seen from space. It is considered a World Treasure Site due to its biodiversity (生物多样性)with 30 species of whales, dolphins and sharks. Within the reef itself, there are also a number of tiny organisms and fishes.

However, its health is threatened. After the recent mass bleaching (白化)events, Veron dived in many areas of the Great Barrier Reef to see the damage for himself. “I was seeing and feeling it and it was absolutely shocking, ” he says.

Veron says the mass bleaching events in the past few years-and the possibility of losing one of nature’s greatest treasures-were a wake-up call for the world in the wider battle against climate change, which, together with the rising sea temperature, is considered the greatest threats to the reef.

Fortunately, earlier this year, the Australian government announced nearly 400 million dollars in new funding towards scientific projects designed to help the reef.

There has been criticism in Australia about the slow process for the funding. “It won’t be wasted, though,”Veron says. “As scientists will be able to create a sort of seed bank to protect the species until the climate is good enough to rebuild the reef. What the scientists hope to do is to help nature along a bit after the big carbon dioxide increase is over and it starts to come down.”

3 . Ho Khanh is a middle-aged farmer, living in a village on the edge of Phong Nha-Ke Bang National Park in Vietnam. What is special about him is that he has discovered Son Doong, the largest cave in the world.

"I first found the cave about thirty years ago, in 1991," he says. "I was out collecting firewood near the national park. My family were very poor, so I decided to go deeper into the forest to find some aloe, which is very valuable. Not many people went that far into the forest because they were afraid of the wild animals."

Soon Khanh lost his way. "I sat down with my back to a huge round rock," he says. "Then I heard the sound of a strong wind and running water coming from behind me." He found the entrance to a huge cave, with a wide river coming out of it. Khanh thought he was walking into a great cave. With no ropes or lights, he did not go further into it.

Khanh's story spread like wildfire, but not everyone believed him. "I wanted to prove that I was telling the truth, but I couldn't remember the way to the cave." Then one morning early in the winter of 2006, a group of cavers from Britain came to ask Khanh for help, as they had heard about his discovery fifteen years before.

Khanh agreed to help the team to find the cave, but after three days in the jungle, they lost their way. "I just couldn't remember where it was," he says. The team came back twice, but each time they were beaten by the thick jungle. Finally the cavers left.

In 2009, Khanh headed to the jungle one cold winter's morning. "I stopped by a big round rock," he says. "There was the same strong wind, the sound of water running—I knew I'd found the cave at long last. "Soon the British cavers returned and followed Khanh on a six-hour trip deep into the jungle. On April 14 they found Son Doong.