1 . Living in a city is a well-known risk factor for developing a mental disorder, while living close to nature is largely beneficial for mental health and the brain. A central brain region, the amygdala (大脑杏仁核) involved in stress processing, has been shown to be less activated during stress in people living in rural areas, compared to those who live in cities, hinting at the potential benefits of nature. “But so far the hen-and-egg problem could not be resolved, namely whether nature actually caused the effects in the brain or whether the particular individuals chose to live in rural or urban regions,” says Sonja Sudimac.

To achieve causal evidence, the researchers from the group examined brain activity in regions involved in stress processing in 63 healthy volunteers before and after a one-hour walk in Grunewald forest or a shopping street with traffic in Berlin. The results revealed that activity in the amygdala decreased after the walk in nature, suggesting that nature elicits beneficial effects on brain regions related to stress.

“The results support the previously assumed positive relationship between nature and brain health, but this is the first study to prove the causal link. Interestingly, the brain activity after the urban walk in these regions remained stable and showed no increases, which argues against a commonly held view that urban exposure causes additional stress,” explains Simone Kühn, head of the group.

The authors show that nature has a positive impact on brain regions involved in stress processing and that it can already be observed after a one-hour walk. This contributes to the understanding of how our physical living environment affects brain and mental health. Even a short exposure to nature decreases amygdala activity, suggesting that a walk in nature could serve as a preventive measure against developing mental health problems and reducing the potentially disadvantageous impact of the city on the brain.

In order to investigate beneficial effects of nature in different populations and age groups, the researchers are currently working on a study examining how a one-hour walk in natural versus urban environments impacts stress in mothers and their babies.

2 . Rachel had a healthy life both physically and mentally till one unfortunate winter evening. It was raining cats and dogs; everything was wet. Rachel’s cat went outside in this cold weather. She ________ him to bring him back inside. He hid near a utility pole (电线杆). Since it rained heavily the pole was charged and ________ to touch. Rachel, bent down to ________ her cat. She held the pole for support not ________ it was charged. The pole electrocuted her so badly that she was barely ________ seconds before her death. The electrocution resulted in ________ both her arms, which had to be cut off.

Rachel had to face such a (n) ________ accident. People get ________ about losing a finger. What would it be like if you lose both your arms? That’s what Rachel was trying to digest. It wasn’t easy at all. Rachel, slowly and gradually was accepting the ________ that she lost her arms and was ________ dependent on others for basic necessities that ________ the use of her arms. It upset her that she could not ________ her own duties herself.

Many people would lose hope. ________, that was not the case with Rachel. She did not want to ________ her dream. She didn’t let the slightest hopelessness bring her down and make her ________ her motivation. After recovery, Rachel ________ day and night to do most of her work with her feet. She emphasized mostly on ________ since she had no arms to do that with. She tried and tried. After many ________ and failures, she finally could write with her feet. She continued her school, ________ her examination and got a scholarship for law school.

Her optimism paved the way for a bright future. Her hard work ________ all because she never gave up.

4 . Mark Baker’s appreciation for nature runs deep, but he hasn’t always championed the Amazon rainforest’s rugged beauty.

For eight years, Mr. Baker’s business sold rare tropical wood from the Amazon to customers across the United States. Exporting wood provided him with an excuse to spend a lot of time in the rainforest, taking him back to his boyhood days. Mr. Baker told himself that selective harvest was just part of managing the resource.

But gradually he began to notice on his birding outings that the forest had grown quieter. On the Manaus docks, he saw wood for export labeled with the name of a type of wood legal to export, but knew that it was another illegal type. “It took me eight years to come to the realization that the construct that you can selectively harvest and manage the forest was a bunch of nonsense,” he says. “I couldn’t do it anymore.”

Because of his own personal transformation, Mr. Baker founded an ecotourism company that takes tourists along Brazil’s Rio Negro. With the trips, he aims to foster appreciation and a sense of stewardship(管理)for the rainforest among global citizens.

The Amazon rainforest covers more than 2.3 million square miles and is the biggest carbon store in the world, according to Giordane Martins, a biologist. Forty percent of Brazil’s land lies in the Amazon, but roughly 20% of it is already deforested. Ecotourism, what Mark is doing, has a positive impact.

“Our role is to educate,” Mark says. “Many people arrive with that nature sensibility. Some acquire it on our tours. One of the goals of ecotourism is to share the economic benefits of travel. The other is to help promote conservation, to generate income and help protect the forest. We’ve seen that happen. I wish we could say we saved the rainforest. We haven’t. But we have had an impact.”

8 . 4 of the World’s Most Amazing Train Journeys

Start: Beijing                  End: Lhasa

Distance: 2,330 miles       Duration（时长）: 40 hours

Connecting Beijing with Lhasa, the Z21 train transports its passengers from a modern city to a mysterious land. What’s unusual is that the train climbs nearly 16,400 it on its journey to the roof of the world: the Tibetan plateau, where it passes yaks, flying prayer flags and snow—covered mountains.

Start: Hanoi                    End: Ho Chi Minh City

Distance: 1,072 miles       Duration: two days

Some railways run through historic cities, others run beside beautiful coastline and a few are famous for the colorful characters on board. The Reunification Express meets all these conditions. It travels over a thousand miles from Hanoi in the north to Ho Chi Minh City in the south. There’s no better way of exploring all the glories in between.

Start: Chicago                  End: San Francisco

Distance: 2,438 miles        Duration: 52 hrs 40 mins

As for appreciating the breathtaking scenery of the North American continent, nothing compares with Amtrak’s California Zephyr train. This journey travels nearly 2,500 miles across prairies, deserts, the Rocky Mountains and the Sierra Nevada on its way.

Start: London                       End: Fort William

Distance: 509 miles               Duration: 13 hrs 30 mins

Starting from crowded central London to the dry and cold air and beautiful views of the Scottish Highlands through one overnight train journey is a perfect example of experiencing the romance（浪漫）of rail travel. It’s just a pity that the whole experience—from delicious foods and drinks to being taken into la-la land—feels like it’s over very quickly.

10 . A team of divers has recently discovered what’s believed to be the longest underwater cave in the world, just three miles from the white sand beaches of the Mexican resort (度假胜地) of Tulum.

The findings confirm that the huge 164-mile-long Sac Actun system is connected to the 53-mile-long Dos Ojos system, bringing the total length of the caves to amazing 216 miles. Some of the caves have a depth of more than 332 feet.

With more than 200 caves, they thought there was chance that something record-breaking would be found below the surface-they just had no proof-until now. Divers have long known that Tulum’s underground caves and rivers are frequently connected, but finding this connection was a task that involved years of searching through labyrinthine (复杂的) passageways.

More exciting than the amazing underwater photographs coming out of the caves is the possibility of uncovering the secrets of the Maya civilization, which ruled this region before the 16th century.

“The area also has lots of historical treasures,” said underwater archaeologist and project director Guillermo de Anda. “Parts of the region were inhabited by the ancient Maya civilization before the Spanish conquest in the 16th century. The discovery will help us better understand the rich culture in the region.”

The combined cave will be known as the Sac Actun system. But while its size makes it the longest underwater cave, it can’t take the title of the longest cave. That belongs to the Mammoth Cave in the American hillsides of Kentucky-thought to be near double the length. They’ll need to keep diving to beat that one.