Machu Picchu is an unusual site in Peru and one of the most mysterious wonders of the world. Built at almost 10,000 feet on the top of an Andean mountain, the Incas built hundreds of structures made of stone. A large number of Machu Picchu's surrounding structures date back to the early 13th century, but it was considered a chief sacred site far before then. The Inca people changed the large site into a very small but wonderful city, completely self-sufficient and hidden from below. Agricultural terraces (梯田) surrounded the entire city, fed by natural spring water, supporting the entire population.

Inca Trail

    The trail is one of the most famous in the world and regarded as one of the best. It covers only 26 miles, combining cloud forest, green mountain scenery, forest, and plenty of tunnels, paving stones, and ruins. The four-day hike begins slowly but quickly changes into a difficult journey suitable for those in excellent shape. The trail winds through the Andes, leading alongside and through ruins. Though independent hiking was once permitted, now it must be done with a guide.

Funerary Rock

    It is believed that the Funerary Rock at Machu Picchu was used as a place to prepare Inca nobles for preservation, or mummifying (做成木乃伊), a common habit among the tribe. Nobles would be laid out to be mummified by the hot sun and freezing cold nights after their organs were removed. The rock is also famous as a spot from which a view of the city is afforded.

Temple of the Sun

    Within the city's castle, deep within Machu Picchu, is the Temple of the Sun, accessed only by the Emperor and

    Inca priests. It means the Inca's advanced knowledge of religion, weather, and nature, showing the great extent

    Incas went to adapt to and learn about nature. Still unbroken, the temple was built to honor the god Inti, who is exactly the sun. The temple was effectively protected. It was also a very important scientific center, built in half-moon shape with openings facing north and east. The windows' shadows in the center of the temple helped see the start of winter solstice (至日), showing farming season.

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    Next time you raise an eyebrow at the views of your partner, friend, sibling (兄弟姐妹) or colleague, remember they could be helping to make you smarter.

    New research shows that intelligence is not fixed but can be boosted throughout adulthood by family members, bright mates and intellectually stretching (拉伸) careers.

    The study challenges the commonly held belief that intelligence is static by the age of about 18. Current scientific consensus suggests that intelligence is controlled by genes, with environmental factors such as schooling and nutrition playing a partial role up to this age. After this point, IQ scores stabilize (稳定).

    But James Flynn, professor of political studies and psychology at the University of Otago in New Zealand, argues that people can “upgrade” their own intelligence throughout their lives. He believes intellectual stimulation (刺激) from others is crucial as the “brain seems to be rather like a muscle – the more you use it, the stronger it gets”. However, the opposite is also true – so people sharing a home or workplace with those who are intellectually challenged risk seeing their IQ levels fall as a result.

    He found the “understanding quality” of a family changes the IQs of all members, especially children. It can “lift” or hold back, depending on the “gap between their brightness and that of their siblings and parents”. A bright ten-year-old with brothers and sisters of average intelligence will suffer a five to ten point IQ disadvantage, compared to a similar child with equally bright siblings. However, children with a low IQ could gain six to eight points by having brighter siblings and special educational treatment to help pull them up.

    Professor Flynn also concluded that although genetics and early life experiences determine about 80 percent of intelligence, the remaining 20 percent is linked to lifestyle. This means that people can raise their IQ, or allow it to fall, by ten points or more. Therefore, the best way to boost IQ level is to mix with bright friends, find an intellectually challenging job and marry someone cleverer.

Building your healthy diet

    Although some extreme diets may suggest something else, we all need a balance of protein ( 蛋白质), fat, carbohydrates ( 碳水化合物), fiber, vitamins, and minerals in our diets to keep a healthy body. You don't need to remove certain kinds of foods from your diet, but rather select the healthiest ones.

Protein

    Protein gives us the energy to get up and go — and keep going — while also supporting mood and cognitive function. Too much protein can be harmful to people with kidney  ( 肾 )  disease,  but  the  latest  research  suggests  that  many  of  us  need  more high-quality protein, especially as we grow up. That doesn't mean you have to eat more animal products — a variety of plant-based sources of protein each day can ensure your body gets all the essential protein it needs.

Fat

    Not all fat is the same. While bad fat can destroy your diet and increase your risk of certain diseases, good fat protects your brain and heart. In fact, healthy fat — such as omega-3s — is necessary to your physical and emotional health. Understanding how to include more healthy fat in your diet can help improve your mood and your well-being.

Fiber

    Eating foods high in dietary fiber (grains, fruit, vegetables, nuts, and beans) can help you stay regular and lower your risk of heart disease, stroke, and diabetes. It can also improve your skin and even help you to lose weight. Depending on your age and gender, nutrition experts suggest you eat at least 21 to 38 grams of fiber each day for optimal (最 佳的) health. Unfortunately, most of us aren't eating even half that amount.

Calcium (钙)

    Your body uses calcium to build healthy bones and teeth, keep them strong, send messages through the nervous system, and regulate the heart's rhythm. Not getting enough calcium in your diet can also lead to anxiety, depression, and sleep difficulties. Whatever your age or gender (性别), it's necessary to include calcium-rich foods in your diet.

    By trying to tickle(挠痒痒) rats and recording how their nerve cells respond, Shimpei Ishiyama and his adviser are discovering a mystery that has puzzled thinkers since Aristotle expected that humans, given their thin skin and unique ability to laugh, were the only ticklish animals.

    It turns out that Aristotle was wrong. In their study published on Thursday, Ishiyama and his adviser Michael Brecht found that rats squeaked and jumped with pleasure when tickled on their backs and bellies. These signs of joy changed according to their moods. And for the first time, they discovered a special group of nerve cells. These nerve cells made this feeling so powerful that it causes an individual being tickled to lose control.

    To make sure that he had indeed found a place in the brain where tickling was processed, Ishiyama then stimulated that area with electrical currents. The rats began to jump like rabbits and sing like birds.

    “It's truly ground-breaking,” said Jeffrey Burgdorf, a neuroscientist at Northwestern University who reviewed the paper. “It takes the study of emotion to a new level.”

    Burgdorf has played a central role in our understanding of animal tickling. He was part of a team that first noticed, in the late 1990s, that rats made special noises when they were experiencing social pleasure. Others had already noted that rats repeatedly made short and high sounds during meals. But the lab where Burgdorf worked noticed that they emitted similar sounds while playing. And so one day, the senior scientist in the lab said, “Let's go and tickle some rats.” They quickly found that those cries of pleasure doubled.

    “The authors have been very adventurous,” said Daniel O'Connor, a neuroscientist at Johns Hopkins University who studies touch. To him, that finding was very surprising.

    “Why does the world literally feel different when you are stressed out?” he said. “This is the first step towards answering that question. It gives us a way to approach it with experimental rigor(严谨).”

    For years I have had no idea what I have been doing with my life. I was a 30-year-old lawyer in New York. But being a lawyer was never my dream or goal in life. I honestly wanted to be a writer. I have a great imagination and would write amazing stories in my head. But I always knew that being a writer was never possible for me because it was a better financial decision to stay a lawyer.

    Recently, I couldn't fall asleep at my usual time of 10 p. m. and when I did fall asleep I had the same dream over and over again. The dream starts with me in the ocean trying to go for a swim and I'm searching for something, but I start to drown and have no control over my body. Then a light shines through the waters and when I look up all I can see is myself in a bright white room writing a novel. Then I hear a voice say repeatedly, “Now is the time to try something new!”

    It wasn't just a dream; it was my opportunity to make something good out of my life. That afternoon, I quit my job at the law firm and I couldn't have been any happier. My life started at 30, and every day since that point I haven't stopped enjoying life. I started to write and have been on the best-sellers list for the last two months. Things have definitely turned around.

    Change is a good thing; it gives us an opportunity to take a chance. So my two favorite words I live by and so should you are “change and chance”.

"What beautiful music!" I shout loudly as my 9-year-old son practices playing the violin. He's used to this praise; I give rewards like that most days. But every once in a while, I skip it, and when I do, I can see the disappointment on his face when he's finished.

Am I a bad mom? Conventional wisdom says that consistency is key to parenting since it enables your child to predict how you'll react, leading to good behavior. And it's true that children need some level of predictability in their lives, particularly when it comes to discipline.

But research suggests that inconsistent gifts and praise can have a greater effect on motivation. While we all like to live in a predictable world, we often respond more strongly to unpredictable rewards.

In one experiment, my colleagues and I told participants they'd be paid if they could drink about one-and-a-half quarts of water in two minutes or less. In one condition, we offered people a $2 fixed reward. In another, there was an uncertain reward of either $2 or $1. The certain reward was a better deal, yet many more people successfully met the challenge when assigned an uncertain reward. Resolving the uncertainty—whether they would win $1 or $2—was significantly more motivating than winning $2 for sure.

Here is one of the reasons why uncertainty is motivating. What scientists call "intermittent (间歇性) reinforcement" —rewarding behavior on some but not all occasions—makes it morearduous to know when rewards will show up. If you very often, but don't always, praise your child for completing their chores, they'll keep up the good behavior in the hope of receiving praise the next time.

So don't assume that if kids are always praised for finishing their homework, they'll be more likely to do it. Do praise young people for a job well done, just not every time. And pick rewards out of a hat when they complete chores—the surprise prize might keep everyone motivated to get things done.