500 million years ago, Natural History Museum
Famed fossils are a link to some of the first complex creatures on earth
Author Jerry Adler writes in our 101 Objects Special Issue:
This was the full flowering of the “Cambrian explosion,” the sudden appearance of a vast new panoply of life-forms—creeping, burrowing and swimming through seas that had held nothing like them in the previous three billion years. Cambrian fossils are known from many sites, but usually only from remains of shells and other hard parts; here, owing to some accident of geology, entire organisms were preserved with eyes, tissue and other soft parts visible.
Read more of Adler's essay.