Legend once had it that the huge, three-toed footprints scattered across the central highlands of Bolivia came from supernaturally strong monsters — capable of sinking their claws even into solid rock. Then scientists came here in the 1960s, determining that this wind-swept plateau was actually the stomping ground of gigantic, two-legged dinosaurs. Now, a team of researchers has discovered 16,600 footprints belonging to theropods — the dinosaur group that includes the Tyrannosaurus rex — in ancient waterways. Paleontologists mostly from California’s Loma Linda University, along with Bolivian researchers, published a study in the peer-reviewed journal PLOS One last Wednesday, claiming this finding represents the highest number of theropod footprints recorded anywhere in the world.