The Burgess Shale fossils were discovered in 1909 by paleontologist Charles Doolittle Walcott of the Smithsonian Institution. The discovery was one of the most important finds in the history of paleontology (the study of fossils and the history of life). The Burgess Shale contained a broader range of animals than any other Cambrian fossil deposit known at the time. A sudden underwater mudslide preserved these creatures in exquisite detail — hard parts, soft parts, and all.

Courtesy Smithsonian Institution