1 . The Best Caves in The World

Natural caves don’t come much larger than Hang Son Doong, close to the border between Laos and Vietnam. This cave possesses the largest cross-section of any known cave on the planet, a vast area that is difficult to describe. Supposedly, a Boeing 747 could fly through without damaging its wings, but that doesn’t really do justice to the vastness of Hang Son Doong. The stalactites (钟乳石) here are pretty massive too, with some reaching up to 80 metres.

Glowworms (萤火虫) are there, as far as the eye can see. Okay, not literally, but the Waitomo Cave system on New Zealand’s North Island is best-known for the fluorescent fauna that light up the walls, giving it the not-particularly-creative but completely acceptable “Glowworm Caves” nickname. They are more accessible than other caves on this list, with rafting and adventure tours available to those looking for something a little more thrilling.

If you have certain expectations from somewhere called “Mammoth Cave”, that is entirely understandable. Mammoth Cave in Kentucky is the world’s longest known cave system, an incredible 420 miles of underground wonder. That’s twice as long as the next longest, by the way, although it isn’t unusual for the USA to go all out on such things.

Named after the reeds that grow outside, which are used to make flutes, obviously, the Reed Flute Cave’s walls are covered with inscriptions from centuries gone by—if evidence was needed that people have been paying attention to this place for a long old time. The inside part of the cave is also lit up by multicoloured lights, giving it a real otherworldly theme that adds weight to the nickname.

2 . National parks are an excellent way to explore all the beauty that the world has to offer: whether it’s endangered species, erupting volcanoes and snowy mountains, or rainforests and lakes. Of the thousands of national parks that exist in the world, these are the ones that should be on everyone’s bucket list.

Contrary (相反) to the popular link of national parks with the wilderness, it is filled with winding valleys, hills and villages where over 24,000 people live and work. Visitors can walk through grassland, visit waterfalls or explore underground caves, but Yorkshire Dales is also home to several food shops, and the park hosts cheese festivals and farmers markets regularly, so it’s best to go hungry.

It is a delight for those who like a bit of history mixed with the biodiversity of national parks. While it houses thousands of species of wildlife, there’s more to the national park than that.

It is surrounded by striking natural beauty and can be explored by land. But the river national park, as the name suggests, is best explored through leisurely boat rides that take visitors through many ancient towns that come along the way of the river.

Here’s a surprising fact: The whole of Vatnajökull National Park makes up 14% of Iceland’s territory! The park is usually open for hikes around the glaciers; boat rides through glacier lakes, and tours that take visitors through the park’s many ice caves, waterfalls, and icebergs. Vatnajökull is also where two of Iceland’s most active volcanoes are located.

7 . This is the story of Moyo, a rescued elephant in Zimbabwe Elephant Nursery, a local non-governmental organization called Wild Is Life. She is probably one of the ________ elephant cubs ever to be rescued. She came to the nursery when she was about three to four ________ old. Sheweighed 56 kilos, and ________ a just-born African elephant cub weighs about 90 kilos. So she was a special iconic little elephant. Under good care of the staff there, she managed to ________.

Every year, hundreds of young elephants are orphaned across the African continent and rarely have a chance of ________ in the wild and are more often than not, left to die. “We rescue babies, and we provide ________ for them. We make sure they are in good ________ here, and help them regain their ________ needed in the wild. We are trying to create a culture where people ________,” said Roxy Danckwerts, the founder of Wild Is Life.

Moyo is about four and a half years old now. She is healthy, playful, and has become some kind of ambassador to the nursery. Therefore, she’s having to take on a lot of ________ for such a young animal, almost becoming a leader at the very young age. She is gentle, calm, very very ________ to the other elephants that come into the nursery. She is also very good with people.

But unfortunately, they’re not much more than objects of money in the eyes of ivory(象牙) dealers. Zimbabwe has a ________ elephant-hunting problem. Some regions are ________ as much as 75 percent of the elephant population over the past 10 years. That is why Danckwerts feels excited at China’s decision to ________ illegal ivory sales, which he believes has become a major turning point and a signal to the world that China has made a ________.

9 . It is well known that rhinos (犀牛) have poor eyesight, so they mostly rely on their noses to understand the world around them. But there’s one interaction in which sound plays a key role. Southern white rhino males can either be dominant (支配地位的) or subordinate. And only the dominant males hold and defend territories. New search finds that they can distinguish the calls of other males to know who is who.

“ We found that contact calls carry information about the dominance status of the males. It means that only by listening to the calls, you can say if the male is territorial or subordinate.” Ivana Cinkoval, a zoologist at the University of KwaZulu-Natal in South Africa.

She and her team spent almost two years in South Africa’s Hluhluwe-iMfolozi Park recording the social contact calls of male rhinos. Then they played those calls back to dominant territorial males and watched the responses.

The researchers asked that the rhino calls not be included in this program due to the concern that calls might be used for illegal hunting. Back to the reactions of the rhinos.

“They started to search for the unexpected visitor the most quickly and spent the longest time searching around for the unwelcome visitor after the playback of the subordinate call, which was quite surprising.”

Only territorial male rhinos hold breeding (交配繁育) opportunities with the female rhinos. Subordinate males could thus be interested in challenging the territorial male for dominance. But dominant males rarely lose their territories to subordinate males, at least while they’re in prime condition.