that don't wind down gradually, but they build up -- get richer and more powerful -- and then within a short time, within a few decades after their peak, they collapse. For example, the classic lowland Maya of the Yucatan began to collapse in the early 800s -- literally a few decades after the Maya were building their biggest monuments, and Maya population was greatest.
并不是逐渐衰弱然后消亡，而是国力逐渐强盛， 势力逐渐扩大，最后达到鼎盛期。突然，在一个极短的时间里， 如几十年间，他们就崩溃了。比如说， 尤卡坦半岛的低地古典玛雅，他们崩溃于 9世纪早期，而正是在此之前的数十年，玛雅人 完成了他们最大的纪念碑，而且，人口数量也达到了史上最多。