The race skywards began in America. In the late 1800s, industrialization had driven urban populations and land prices up, making tall buildings increasingly cost-effective. Like all major shifts in architecture, the trend was supported by engineering. The development of steel frames made it easier to build tall. The invention of the lift, meanwhile, made living in higher floors far more convenient.

Though similar in shape, today's skyscrapers look little like those built in the first half of the 20th century. This is mostly thanks to the curtain wall. Postwar developments in manufacturing (制造) meant that huge sheets of glass could be produced quickly and uniformly, and the curtain wall soon became the front of high-rises. As well as allowing for greater floor space and more natural light, glass surfaces help buildings bear greater wind loads.

There are now 191 completed skyscrapers that are at least 300 meters tall. But that doesn't mean our cities will grow taller indefinitely. While each additional story adds sellable floor space, construction costs also rise. All buildings reach a point where adding an extra floor will cost more money than it generates.

This reality can certainly be felt in America. Though skyscrapers began as a US phenomenon and continued increasing there in the 1960s and 1970s, the Middle East and Asia now dominate high-rise construction. This is partly due to the lower construction costs in Asian and other non-Western countries. However, it may also demonstrate that skyscrapers are about more than the return on investment---they are a matter of branding. And in some cities, building tall can be a necessity.

The next big challenge facing architects goes beyond height: At a time when buildings and their construction account for more than a third of the world's energy consumption and contribute about 40% of greenhouse gas emission (排放)，there are new environment-friendly costs to consider.

People climbing Mount Everest are two times as likely to reach the top and less likely to die on the climb than 20 years ago, a new study finds. Everest, high in the Himalayans, is the tallest mountain above sea level on Earth. It reaches 8,848 meters into the sky.

Between 2006 and 2019, around two thirds of climbers were successful in their attempt to reach the top. In the 15 years before that, only about one—third went all the way to the top.

The number of attempts to reach the top of Everest has risen sharply over the years, leading to a 300 percent increase in overcrowding. In 2019, 955 climbers tried to reach the mountaintop. Only 222 people did so in 2000.

The study noted that on a single day in May of last year, 396 climbers had gathered at the narrow path just below the top. The area, known as the “death zone,” is so narrow that only a small number of climbers can pass through, one directly behind another.

Nine climbers died on Everest in May 2019. It was the deadliest Everest climbing season since 2015 when an earthquake killed at least 18 people on the mountain.

A picture of climbers waiting their tun to go up and down through the death zone became famous as it was shared online. Yet researchers say the crowds were not the main reason for the deaths last year. “Surprisingly crowding has no evident effect on success or death” of Everest climbers, the study said.

However, overcrowding does make the climb more dangerous. “If crowding slows climbers (as is expected), this increases their exposure to the elements, which should increase risk of an accident or illness,” said Raymond B. Huey, lead writer of the report.

An unexpected storm, earthquake, or landslide could be disastrous, he told Reuters by email.

Climbers have expressed concern about giving anyone willing to pay the government $11,000 permission to climb Everest. Nepal plans to change its policy to require climbers to use guides, and meet physical fitness and experience qualifications, said tourism department official Mira Acharya.

Nepal temporarily closed its mountains to climbers because of the coronavirus health crisis. Now they are open again. However, Acharya noted that flights into and within Nepal have not restarted.

Most people know social media isn’t free — it’s paid for with the collection of its users’ sometimes-sensitive information. Your GPS system keeps track of your movements, and your smart TV can watch you. Almost all the information these devices collect can be sold to companies or used by authorities to keep tabs or gather evidence. Meanwhile, we use technology so frequently because of its efficiency and convenience. Is the trade-off worth it, or are we selling our souls to the devil?

SafeHome.org Team surveyed 1,019 people aged 18 and older about their opinions on security and electronic devices and whether they felt the risk to privacy was worth the security and convenience benefits. As it turns out, some feel technology is far too convenient to give up despite its flaws, while others would trash their devices if they found out it was spying on them.

Interestingly, three major factors appear to have an impact on which aspect of privacy violation they find most shocking — age, gender and occupation.

Different generations have different relationships with technology and, as such, have different concerns about privacy. Those 65 and older appeared to be very distrustful of technology, recording higher levels of concern than younger generations in almost every field. Those aged 45 — 64 all found location tracking, home security, and smart device privacy issues to be the most threatening. From age 18 to 44, the data trends looked rather similar. A distrust of social media existed, but they regarded fitness trackers, and public surveillance (监视) as less of an issue than older generations.

While men and women seemed to have the same concerns about privacy in the digital age, a few interesting aspects existed. Women were more concerned overall with identity and location tracking. Men had concerns with these issues as well but perhaps didn’t feel as physically threatened by them. The place where men took more issues than women was the selling of personal data to advertisers and monitoring of conversations and activities.