Central to all High Mountain Institute programs is extended experience in outdoor adventure. Each course goes into great depth to develop students' outdoor skills, leadership, and environmental awareness. Through living and traveling with a small group of peers and instructors, students focus on practicing leadership and the ability to work effectively in a team.

Program Starts: Fall, Winter, Spring, Summer

Program Duration: Less than 2 months, Semester, Yearlong

Typical Program Cost: $6,200—$9,500

Raleigh Expedition is an international volunteering program run by Raleigh International, which engages volunteers in creating long-lasting change on community, environmental and adventure leadership projects. All Raleigh's work contributes towards the sustainable development goals, starting with developing the skills of young people.

Program Starts: Fall, Spring, Summer

Program Duration: Less than 2 months, Semester, Yearlong

Typical Program Cost: $5,100—$6,150

Founded in 1947, CIEE is the oldest and largest nonprofit study abroad and intercultural exchange organization in the United States. The Language and Culture Programs enable students to immerse themselves in the local scene while improving their fluency in Spanish, French, German, Italian, Japanese or Arabic. The high quality programs provides participants with skills and experiences that elevate their ability to contribute positively to their global community.

Program Starts: Fall, Winter, Spring, Summer

Program Duration: Less than 2 months, Semester, Yearlong

Typical Program Cost: $9,800—$16,000

Youth International offers experiential learning programs that combine volunteer community service work, home stays with local families, international travel, and outdoor expeditions. Developing more personally and socially aware future leaders, it also hopes to take small steps toward bridging the gap between people of different nations.

Program Starts: Fall, Spring

Program Duration: Less than 2 months

Typical Program Cost: $4,950—$5,950

Early one morning in February, a team of specialists pulled up next to a building in Nottingham. They worked quickly but carefully, removing a small section of the wall on which "Hula-hoop Girl" had been painted by Banksy, an outstanding street artist. John Brandler, a collector, said that he had purchased the artwork from the building's landlord. Local residents were horrified, as the mural (壁画) had spread cheer during the lockdowns in Britain.

It was not the first time Banksy's artwork had been carried off. So many of Banksy's pieces, in particular, have been taken and sold into private collections that they have been brought together to form an exhibition. "The Art of Banksy", the world's largest display of his work, opened in London in May as a paid-for, ticketed exhibition. The show invites art lovers to take cash out to view privately held works intended to be publicly accessible and free. Banksy has criticised the practice, saying that he will not authenticate artworks removed from their original site.

Street art is an unusually risky art form. Painters rarely seek permission to turn a building into a canvas, and so while the artwork belongs to them, the backdrop does not. If they want to protect their pieces from unwanted buyers, artists should ask for permission from the building owner and sign a contract. Another different problem is posed by many street artists' decision to remain anonymous. Artists shield themselves from accusations of deliberately damaging public property by using secret identities, but potentially lose out on the chance to protect their works from copyright theft.

But the legal protections are improving as more people come to appreciate street art's value. Ina case last year, a judge found that famous graffiti (涂鸦) in New York was protected from removal because it had "significant artistic value and cultural importance". Copyright lawsuits are also increasingly common.

Allergies（过敏）cause loads of trouble. Some people suffer from seasonal hay fever as pollen（花粉）flows through the air. Others react to materials at their very touch. And some sorry souls go into shock at the mere presence of certain foods, particularly peanuts and shellfish.

The cause in each case is an oversensitive immune system. This creates annoying and sometimes life-threatening symptoms. Over-reactive immune systems may not, though, be an entirely bad thing. Another role played by the immune system is to destroy malignant tumors（恶性肿瘤）before they take hold—work carried out recently by Annette Wigertz of the Karolinska Institute, in Stockholm, and her colleague suggests that the immune systems of those with allergies may be particularly good at this.

This finding came after Doctor Wigertz and her team interviewed 1, 527 people with gliomas（a type of brain tumor）in Denmark, Finland, Norway, Sweden and the southeast of England. The researchers asked the patients in question whether they had a history of allergies, and then compared the results with those for 3, 309 otherwise similar individuals who did not have brain tumors. As Doctor Wigertz reports in the American Journal of Epidemiology, the tumor-free were more likely to suffer from allergies. The presence of an allergy was associated with a 30% reduction in the likelihood of having a glioma.

This was not all that surprising. Previous research had detected similar correlations, suggesting that a welcome side effect of allergy was resistance to cancer. But this new study went further. It looked carefully at the time in the patients' lives when their allergies were active, and it found that this timing was crucial. Doctor Wigertz noted that the absence of allergy was correlated with the time when the glioma first formed.

Awkwardly, this result is open to two rather different interpretations. The optimistic explanation is that the hyperactive immune system associated with allergy does protect against tumors. The other interpretation is that tumors are doing something as they grow that stops the immune system and thus allergic reactions. Either way, tumor and lack of allergy coincide. And either way, something interesting is going on.