A gap year is a year off after middle school and before university. In 2000, a fifth of all British students took one. Most use the time to travel to other parts of the world. In the last two years, there has been a burst in the number of young people going traveling. Cheap flights, plenty of travel books and well-trodden ( 成熟的 ) routes make it much more likely for them to get on a plane and fly over to the other side of the planet. The average cost of a student round-the-world ticket is £850. A six-month trip will set you back about £2,000. Come the two-month summer holiday in university and everyone’s off again. Student loans and savings are eagerly thrown at travel agencies such as STA Travel—the largest youth travel operator in the world to get discount ( 折扣 ) flights to places like Thailand, Nepal and South America. But the fastest growing market is the 25-35 age-group, known as “career gappers.” After university and early in their careers, more of these graduates are making the most of affordable flights before being tied down by a relationship or even a pet cat.