When the Normans built their first simple wooden castles in England，they built them on the top of small hills.The first permanent castles were made of stone and built with thick walls.The main building was usually surrounded by walls which overlooked the moat (护城河)．

     The entrance to the castle was usually over a drawbridge (吊桥) leading to the main gatehouse.The drawbridge could be raised or lowered and an iron grille (栅栏) could be lowered to shut off the entrance to the gatehouse.

     As time went on，the castle builders became more advanced in their techniques.Instead of building a strong central building and surrounding it with walls of lesser strength，they thought out the idea of surrounding a central area with huge walls which could contain all the main rooms of the castle.These walls usually had many towers and these towers were really a series of main buildings along the castle walls.In building these castles they used hill sites whenever possible in order to give the castle a better position.Because the outside world was shut off by a barrier or curtain of defences，they are called “curtain wall” castles.

     With the passing of time there was less need to build strong castles and nobles built manor (庄园) houses.These manor houses often had battlements and iron grilles，but they were built more for comfort and included many of the conveniences and luxuries of the large houses which were being built in the towns.

     Unfortunately，many English castles were damaged or destroyed completely during the Civil Wars of the 1600s.

    Would it surprise you to learn that, like animals, trees communicate with each other and pass on their wealth to the next generation?

    UBC Professor Simard explains how trees are much more complex than most of us ever imagined. Although Charles Darwin thought that trees are competing for survival of the fittest, Simard shows just how wrong he was. In fact, the opposite is true: trees survive through their co-operation and support, passing around necessary nutrition（营养）“depending on who needs it”.

    Nitrogen（氮）and carbon are shared through miles of underground fungi（真菌）networks, making sure that all trees in the forest ecological system give and receive just the right amount to keep them all healthy. This hidden system works in a very similar way to the networks of neurons（神经元）in our brains, and when one tree is destroyed, it affects all.

    Simard talks about “mother trees”, usually the largest and oldest plants on which all other trees depend. She explains how dying trees pass on the wealth to the next generation, transporting important minerals to young trees so they may continue to grow. When humans cut down “mother trees” with no awareness of these highly complex “tree societies” or the networks on which they feed, we are reducing the chances of survival for the entire forest.

    “We didn't take any notice of it” Simard says sadly. “Dying trees move nutrition into the young trees before dying, but we never give them chance.” If we could put across the message to the forestry industry, we could make a huge difference towards our environmental protection efforts for the future.

    Earthquakes are something that people fear. There are some places that have few or no earthquakes. Most places in the world, however, have them regularly. Countries that have a lot of earthquakes are usually quite mountainous.

    The most talked about earthquake in the United States was in San Francisco in 1906. Over 700 people died in it. The strongest one in North America was in 1964. It happened in Alaska.

    Strong earthquakes are not always the ones that kill the most people. In 1755, one of the strongest earthquakes ever recorded was felt in Portugal. Around 2,000 people died.

    In 1923, a very strong earthquake hit Tokyo, Yokohama area of Japan. A hundred and forty thousand people died. Most of them died in fires which followed the earthquake.

    One of the worst earthquakes ever was in China in 2008. It killed a large number of people. The worst earthquake ever reported was also in China, in which 400,000 people were killed or injured. This earthquake happened in 1556.

    Earthquakes worry people a lot. The reason is that we often do not know when they are coming. People cannot prepare for earthquakes.

    In Western society, especially in the English-speaking world, the chance for young people to see the other countries and experience life is considered important. Many young people, when they finish school at the age of 18, take a gap year before they go to university.

    Parents often want their children to grow up a little and see what the real world is like when they finish school. Although they are worried about their safety, many think that the advantages of independence and experience are worth the worries. Children are encouraged to be brave, independent and to explore the world on their own or with friends.

    Young people also want to experience freedom and see what life is like on the other side. This other side could be the other side of the world or just the other side of life. For example, if they have a rich life, they may want to see how people in poor areas live.

    A gap year after school is also an important chance for young people to spend time thinking about what they want to do with their lives. A little bit of growing up and experience will help them make their important career decisions, especially when they are unsure about what they want to study.

    Another reason for going straight after school is to get a break from studying before they start the next few years of university. So anywhere you travel in the world, you will meet young European people exploring the world.

    So much of the world has been travelled and explored. The young people are now looking for more worthy experiences. Some of them work as volunteers to do something for the country they are visiting. Many gap year volunteers are now spending a few months teaching English in Thailand, helping feed giant pandas in China or building a well(井) in a village in Africa.

    These young people's wish to explore the world is an expression of the values of the societies that they are part of. Both discovering the world and making a positive difference in it are important parts of the Western mind.

    There are many weird sports that are present from around the world. From each region of the world, along with the very popular common sports, there are also those really popular but very weird kinds of sports.

    The Ultimate Test between Man and Horse:

    This indeed a very strange kind of sport that tests your stamina. You will learn how to be agiler while competing against a horse. This game originated in Welsh town of Llanwrtyd Wells. This sport really has to do with strength. You will require great agility and strength in order to take part in this. Marathon human contestants are put to test against those mounted on horses. This is how the marathon testing takes place.

    Love Locked Race

    This is a sports event that was first introduced in Finland. This is all about a male competitor racing with a female in a certain way. There would be many obstructions and blocks on the way which would definitely bring you challenges. The person to win would have to finish the race without losing his female partner in the course of overcoming the obstacles even for once. This race takes place really fast and the obstacles are set that way.

    Toe sport

    This is yet another weird sport that welcomes you to use your toes. This is quite the same kind of sport that you used to play as a child which involved toe wrestling. This has now been turned into a major sport that even has a World Toe Wrestling Competition. It first originated in a pub of Derbyshire.

    The locals took this sport with great enjoyment and then made this so popular that it soon had its own championship. The individuals who participate have only got to use their feet in locks but then this is tougher than it may sound.

    The Mud Pit Belly Flop

    This is a kind of game where even the spectators get splashed in mud but in fact that is quite the fun. The very annual Summer Redneck Games in East Dublin brings about this game and brings about some of the greatest hubcap discus throws with it. This is also a great sport to show the strength and dexterity of your feet.

    Although it's great to spend vacations seeing the world with family, friends, or a lover, traveling alone can also be completely incredible. A solo adventure has the potential to be life-changing. Here are some reasons you should travel alone at least once.

    If you enjoy meeting new friends, here's your chance; you will likely find some when traveling alone, Since you won't be focused on talking to anyone you know, you'll be more likely to strike up conversations with strangers. Meeting people from different backgrounds opens our minds, expands our world, and can inspire us a lot. You may meet some amazing locals or other adventurers like yourself; either way you're bound to make some new friends during your journey.

    A trip alone can ignite your creativity. Spending time alone with an open mind can be exactly what you need for your imagination to soar. Your enthusiasm and passion for life may sky-rocket from your awesome adventure.

    When traveling with a partner or a group, every idea can be bounced off someone else. When you travel alone, you will learn to be decisive; you will be making every decision alone. From where to eat, to what time to wake up, to what sights to see, and which airline to use, traveling solo forces you to rely on yours truly. As you realize you can make good choices without help from others, you will likely trust your instincts more, and this new found self-assurance and confidence will be helpful in many areas of your life.