Scientists say they have discovered a "stunning" trove of thousands of fossils on a river bank in China.
The fossils are estimated to be about 518 million years old and are particularly unusual because the soft body tissue of many creatures, including their skin, eyes, and internal organs, have been "exquisitely" well preserved.
Paleontologists have called the findings "mind-blowing" - especially because more than half the fossils are previously undiscovered species.
The fossils, known as the Qingjiang biota, were collected near Danshui river in Hubei province.
More than 20,000 specimens were collected, and a total of 4,351 have been analyzed so far, including worms, jellyfish, sea anemones and algae.
They will become a "very important source in the study of the early origins of creatures", one of the fieldwork leaders, Prof Xingliang Zhang from China's Northwest University, told the BBC.
Scientists are especially excited by the jellyfish and sea anemone fossils, which Prof Gaines describes as "unlike anything I have ever seen. Their sheer abundance and their diversity of forms are stunning".
Meanwhile, Prof Allison Daley, a paleontologist who was not part of the study but wrote an accompanying analysis in Science, told BBC's Science in Action programme the find was one of the most significant in the last 100 years.
"It blew my mind - as a paleontologist, I never thought I'd get to witness the discovery of such an incredible site.
"For the first time we're seeing the preservation of jellyfish - you think of jellyfish today, they're so soft-bodied, so delicate, but they're preserved unbelievably well at this site."
