have been one of nature's greatest spectacles for millions of years. 这样的聚集 一直是自然界最壮丽的奇观之一

200. Here, on the edge of the Great Barrier Reef...
     在大堡礁的边缘
201. they come together in their thousands.
     它们成千上万结伴而来
202. Aggregations like this
     数百万年来
203. have been one of nature's greatest spectacles for millions of years.
     这样的聚集 一直是自然界最壮丽的奇观之一
204. There's a good reason for this gathering.
     如此聚集是有原因的
205. Safety in numbers.
     龟多更安全
206. Turtles first evolved back in the Triassic.
     海龟最早是在三叠纪时期进化而来

来自《我们星球上的生命 第一季 第四集 Life on Our Planet S01E04 冷血动物》第 203 行