The great barrier reef is the world's largest network of coral structures.

大堡礁是世界最大的珊瑚礁群。

Which once complete will make it the world's largest natural wonder, albeit sort of man-made, it'll be a whole three times as large as the Australian great barrier reef.

一旦完工，它将成为世界上最大的自然奇观，尽管是人造的奇观，它将是澳大利亚大堡礁的三倍大。