3 . Hanging stockings by the chimney with care is one of the most popular Christmas traditions, but many families display theirs without wondering why. No one can be sure when and why the practice started, but some stories give us a clue.

One of the most popular origin tales starts with none other than St. Nicholas — yes, he was a real person. In the third and fourth centuries, St. Nicholas was a bishop in modern-day Turkey who made helping others his life mission, and he caught wind of a family in need.

As the story goes, a single father was raising three daughters but realized he didn’t have enough money to pay their dowries (嫁妆)---and without dowries, they couldn’t get married.

St. Nicholas heard of the family’s dilemma but knew they were too proud to accept handouts. To make sure they didn’t refuse his generosity, he secretly sent them gold at night. Some legends say he dropped gold down the chimney, and the gifts landed in the stockings that were laid by the fire to dry, while others claim Nicholas himself hopped down the chimney. Someone - either the father or the daughters, depending on the version of the tale - caught the bishop in the act and thanked him for his help. The gifts were enough for the daughters to marry and live happily ever after.

St. Nicholas^, feast day was on December 6, and eventually, the tradition of leaving gifts in stockings was paired up with Christmas celebrations.

That makes a neat and tidy origin story, but some scholars suggest the stocking tradition might have started even before Christianity in Scandinavian cultures. The Norse god Odin was said to come on Christmas, riding on an eight-legged horse. Children would leave sugar, carrots, and hay in their shoes to feed the mythical horse, and Odin would leave them gifts in return.

We’ll never know whether these stories were true or not, but stockings have a strong foothold in Christmas tradition.

4 . It was in my first year of work as a doctor. My mouth was dry, my palms sweaty and my voice trembling. The only thing that kept me focused was the thought that things were so much worse for the family I was talking to.

A woman in her early twenties had been brought in after a road traffic accident. She had suffered multiple injuries and had been rushed up to theatre. The surgeons had been unable to save her life and she died on the table. Ashen-faced, the consultant (会诊医生) told the woman's family the news. “Tom, I think it would be nice if it came from you,” my consultant said.

I stared blankly. “What?” I asked.

“About organ donation,” he replied. I swallowed hard. Surely this would be the last thing they'd want to talk about. It felt acutely awkward and ill-timed to be considering this kind of conversation while they were being engulfed in grief. But the problem with organ donation is that every minute counts. The clock is ticking because the sooner organs can be transplanted, the better the chance they will survive in the recipient's (接受者) body.

I began to feel sick. I opened the door and sat opposite them, convinced that I was only going to make things worse for them.

“It's what she'd have wanted,” the mother said before I'd even finished. The father nodded. “She was always so generous,” her father added.

As my consultant and I left them, it occurred to me that I'd been wrong in thinking it would be an awkward conversation. Nothing could take away the pain of having lost their daughter. Yet this last, final act had comforted them and helped them feel that the spirit of their daughter lived on m this act of generosity. Strangely, it is one of the most heart-wanning conversations I have ever had.

5 . At eleven, I decided to learn to swim. There was a pool at the Y. M. C. A. offering exactly the opportunity. My mother continually warned against it, and kept fresh in my mind the details of each drowning in the river. But the Y. M. C. A. pool was safe.

I had a childhood fear of water. This started when I was three years old and father took me to the beach. The huge waves knocked me down and swept over me.

The pool was quiet. I was afraid of going in all alone, so I sat on the side of the pool to wait for others. Then came a big boy. He yelled, “Hi, Skinny! How'd you like to be ducked?” With that he picked me up and threw me into the deep end. I landed in a sitting position, and swallowed water. But I was not frightened out of my wits—when my feet hit the bottom, I would make a big jump, come out of the surface. It seemed a long way down. I gathered all my strength when I landed and made what I thought was a great spring upwards. Then I opened my eyes and saw nothing but water. I tried to yell but no sound came out. I went down, down, endlessly.

When I came to consciousness, I found myself on bed in hospital. I never went back to the pool. I avoided water whenever I could. This misadventure stayed with me as the years rolled by. It deprived(剥夺) me of the joy of boating and swimming. Finally, I decided to get an instructor. Piece by piece, he built a swimmer. Several months later, the instructor was finished, but I was not. Sometimes the terror would return.

This went on till July. I swam across the Lake Wentworth. Only once did the terror return. When I was in the middle of the lake, I put my face under and saw nothing but bottomless water.

I laughed and said, “Well, Mr. Terror, what do you think you can do to me?”

I had conquered my fear of water.

8 . Although we're surrounded by millions of bricks every day, most of us don't think about them too often. For thousands of years, the humble clay-fired bricks haven't changed.

They're made from natural materials, but there are problems with bricks at every step of their production. Bricks are made from clay—a type of soil found all over the world. Clay mining is harmful to plant growth. In conventional brick production, the clay is shaped and baked in kilns(窑) mostly heated by fossil fuels, which contributes to climate change. Once made, bricks must be transported to construction sites, generating more carbon emissions. With so many bricks produced globally, their impact adds up.

Gabriela Medero, a professor at Scotland's Heriot-Watt University, decided to find solutions to that. With her university's support, Medero set up Kenoteq in 2009. The company's signature product is the K-Briq. Made from more than 90% construction waste, Medero says the K-Briq—which does not need to be fired in a kiln—produces less than a tenth of the carbon emissions of conventional bricks. With the company testing new machinery to start scaling up production, Medero hopes her bricks will help to build a more sustainable world.

The K-Briq will be comparably priced to conventional bricks. Additionally, as a new product, the K-Briq has been subjected to strict assessment and authoritative certification. Reusing old bricks is an expensive process and there is no standardized way to check the strength, safety or durability (耐久性) of recycled bricks. Medero says that K-Briq could solve both these problems. She claims that K-Briq is stronger and more durable than fired clay bricks.

Over the next 18 months, Medero plans to get K-Briq machines on-site at recycling plants. "This will reduce transport-related emissions because trucks can collect K-Briq when they drop off construction waste," says Medero.

10 . As a child, Jane Goodall had a natural love for the outdoors and animals. And at age 23, she left for Nairobi, Kenya. There, Jane met famed Dr. Louis Leakey, who offered her a job at the local natural history museum. She worked there for a time before Leakey decided to send her to the Gombe Stream Game Reserve in Tanzania to study wild chimpanzees. He felt her strong interest in animals and nature, and her knowledge as well as high energy made her a great candidate to study the chimpanzees.

In December 1958, Jane returned home to England and Leakey began to make arrangements for the expedition(考察), securing the appropriate permissions from the government and raising funds. In May 1960, Jane learned that Leakey had gained funding from the Wilkie Brothers Foundation.

Jane arrived by boat at the Gombe Stream Game Reserve on the eastern shore of Lake Tanganyika with her mother. The early weeks at Gombe were challenging. Jane developed a fever that delayed the start of her work. Finally, an old chimpanzee named David Greybeard began to allow Jane to watch him. As a high-ranking male of the chimpanzee community, his acceptance meant other group members also allowed Jane to observe. It was the first time that Jane had witnessed David Greybeard using tools. Excited, she telegraphed Dr. Leakey about her observation. He wrote back, "Now we must redefine 'tool' and 'man' or accept chimpanzees as humans."

Jane continued to work in the field and, with Leakey's help, began her doctoral program without an undergraduate degree in 1962. At the University of Cambridge, she found herself at odds with senior scientists over the methods she used—how she had named the chimpanzees rather than using the more common numbering system, and for suggesting that the chimps have emotions and personalities. She further upset those in power at the university when she wrote her first book, My Friends, the Wild Chimpanzees, aimed at the general public rather than an academic audience. The book was wildly popular, and her academic peers were outraged. Dr. Jane Goodall earned her Ph. D. on February 9, 1966, and continued to work at Gombe for the next twenty years.