Dozens of dinosaur footprints embedded in a boulder were found hiding in plain sight at an Australian school, according to researchers.

Analyzing the size of the footprints, researchers estimate that the dinosaurs had hip heights between 20 and 76 centimeters and were walking at speeds between 2 and 6 kilometers per hour. The environment at the time was likely a silty surface under a shallow layer of water, providing ideal conditions for preserving footprints.