You may know the Eiffel Tower as one of the most famous man-made monuments in the world, and you'd be absolutely right! Read on to learn about the history of the great Eiffel Tower.

    Travelers from around the world flock(蜂拥)to Paris, France, to visit the Eiffel Tower, making it the most visited paid monument in the entire world! In fact, in 2010, the Eiffel Tower welcomed its 250 millionth visitor!

The history of the Eiffel Tower

    The Eiffel Tower was named after the engineer Gustave Eiffel, whose company designed and built the famous monument. Construction began in January of 1887 and was completed in only two years. Their plan was to finish the tower in time to be the entrance arch for the World's Fair in 1889. This fair celebrated the 100^th anniversary of the French Revolution, which took place from 1789 to 1799.

The height competition

    Located on the Champs de Mars, the tower is the tallest structure in Paris. It was the tallest man-made structure in the world for 41 years until the Chrysler Building in New York surpassed(超过) it. Then the spire(塔尖) on the top of the tower was added, raising its height to 17 feet taller than the Chrysler Building. It is now 1,063 feet tall! There are two replicas(复制品) of the Eiffel Tower in the world: a half scale model at the Paris Hotel in Las Vegas and a full-sized monument of a similar (but not exact) design in Tokyo, Japan.

Three shades of wonder

    Some pictures make the Eiffel Tower look like a dark iron color. But it is, in fact, bronze. Not only that, but the tower is actually painted three different shades to make it appear even taller: darkest on the bottom and lightest on the top.

    Most young people enjoy some forms of physical activity. It may be walking, cycling, swimming, or in winter, skating or skiing. It may be a game of some forms—football, basketball, hockey, golf or tennis. It may be mountaineering.

    Those who have a passion for climbing high and difficult mountains are often looked upon with astonishment. Why are men and women willing to suffer cold and hardship, and to take risks in high mountains? This astonishment is caused, probably, by the difference between mountaineering and other forms of activity to which men give their leisure.

    Mountaineering is a sport and not a game. There are no man-made rules, as others, as there are for such games as golf and football. There are, of course, rules of different kinds which would be dangerous to ignore, but it is this freedom from man-made rules that makes mountaineering attractive to many people. Those who climb mountains are free to use their own methods.

    If we compare mountaineering with other more familiar sports, we might think that one big difference is that mountaineering is not a “team game”. We should be mistaken in this. There are, it is true, no “matches” between “teams” of climbers, but when climbers are on a rock face linked by a rope on which their lives may depend, there is obviously teamwork. The mountain climber knows that he may have to fight forces that are stronger and more powerful than man. He has to fight the forces of nature. His sport requires high mental and physical qualities.

    A mountain climber continues to improve in skills year by year. A skier is probably past his best by the age of thirty. But it is not unusual for men of fifty or sixty to climb the highest mountains in the Alps. They may take more time than younger men, but they perhaps climb with more skills and less waste of effort, and they certainly experience equal enjoyment.

    Let's catch a glimpse of the latest inventions this year.

    Parallels lets you use desktop apps on your phone

    You'd think most applications would have created a mobile app by now — but many companies still use desktop apps exclusively. Now Parallels Access lets you access them on your smartphone. All you need to do is download the app, then connect Parallels' Applification™ to your computer, so you can access important files and other apps with a single click. You can easily use your apps in full-screen mode, using intuitive(直观的) touch controls to work faster than before.

    Usually, Parallels Access is $19.99, but you can get it now for $9.99.

    Take your lighting to the next level with this smart switch

    You probably don't spend a lot of time thinking about your home's lighting, but it's important: the way that you control your lighting affects the environment (and your electric bill).

    This WiFi wall switch is controlled via a companion app on your smartphone, so you can control connected lights or ceiling fans from anywhere.

    Usually, the Meross WiFi Wall Light Switch costs $45.99, but right now it's on sale for $39.99 .

    Shoot beautifully clear videos with this smartphone gimbal

    If you're interested in shooting professional-quality videos and photos, you don't have to spend a fortune to take a beautifully composed shot: just use this Rigiet Smartphone Gimbal instead.

    A gimbal is a support for your camera (in this case, your smartphone) that allows it to pivot（移动）, and automatically detect and adjust to the position that you want to film in. Unlike any other camera hardware you might own, this one comes with its own accompanying app.

    Usually, this Rigiet Smartphone Gimbal is $269, but you can get it now for $109.99.

Smart and highly sensitive （灵敏的）, a new soft sensor developed by UBC (University of British Columbia) and Honda researchers opens the door to a wide range of applications in robotics and prosthetics （假肢）.

When applied to the surface of prosthetic or robotic arms, the sensor skin provides touch sensitivity and flexibility, making it possible for difficult tasks to be completed by machines, such as picking up a piece of soft fruit. The sensor is also soft to the touch, like human skin. which helps make human interactions safer and more lifelike.

"Our sensor uses weak electric fields to sense objects, even at a distance, much as touchscreens do. But unlike touchscreens, this sensor is soft and can detect forces into and along its surface," explained Dr. John Madden, senior study author and a professor of electrical and computer engineering who leads the Advanced Materials and Process Engineering Laboratory at UBC.

The UBC team developed the technology in cooperation with Frontier Robotics, Honda's research institute. Honda has been innovating in humanoid robotics since the 1980s, and developed the well-known ASIMO (Advanced Step in Innovative Mobility) robot. It has also developed devices to assist walking and the emerging Honda Avatar Robot.

"Dr. Madden's lab has significant expertise in flexible sensors and we're happy to cooperate with this team in developing touch sensors that can be applied to robots," said Mr. Ishizaki Ryusuke, one of the study's lead authors and chief engineer at Frontier Robotics.

Dr. Madden said, "Human skin has a hundred times more sensing points on a fingertip than our technology does, making it easier to light a match or sew. As sensors continue to develop to be more skin-like, and can also detect temperature and even damage, there is a need for robots to be smarter about which sensors to pay attention to and how to respond. Developments in sensors and artificial intelligence will need to go hand in hand."

Where does the meat on our table come from? It usually comes from livestock like chickens and cows. But did you know that meat can also be made in a lab? US company JUST has announced that lab-grown meat could be on some restaurant menus in the United States and Asia by the end of 2018, The Independent reported.

"These meats include chicken nuggets (鸡块), sausage and foie gras (鹅肝酱)," Josh Tetrick, CEO of JUST, told The Independent. Lab meat is sometimes referred to as "clean meat". It is made using the stem cells (干细胞) of living livestock. The cells need to be grown in a lab for a few weeks. For example, making a hamburger patty (肉饼) takes about nine weeks, CNN reported. This is faster than raising a cow, which usually takes over 20 weeks.

The first clean meat was a beef burger that was produced in 2013, but it was said to taste quite dry. How does clean meat taste now? Clean meat supporters told CNN that they think it tastes just like traditional meat.

Clean meat has other advantages. It is healthier than traditional meat. Meat producers can control what type of fat goes into the meat. They can produce clean meat that contains healthy fats, such as omega-3 fatty acids (脂肪酸). This kind of fat is good for people's hearts.

Clean meat can also help to solve global warming. According to The Washington Post, about 14.5 percent of the planet's greenhouse gas emissions (排放) come from raising livestock. That's more than the emissions from every car, train, ship and airplane in the world combined. It is predicted that switching to clean meat could lower greenhouse gas emissions by 96 percent, The Independent reported.