Even half a century ago, paleontologists and biologists were puzzled by the huge strata of “silent” rocks without traces of multicellular life and its sudden – by geological standards – appearance in the Cambrian period (the so-called Cambrian explosion). But then it became clear that even the most delicate organisms left marks in the geological record. Scientists who have figured out what and where to look for are now actively exploring the “speaking” Precambrian - a real “lost world” inhabited by original organisms that are not similar to modern ones.