Scientists have unearthed largest collection of dinosaur footprints ever found in Bolivia's Torotoro National Park. The 16,600 tracks were made by theropods, the predatory cousins of Tyrannosaurus rex. The footprints range from less than 10cm to over 30cm in size and also show toe splay, tail drag marks, and even small turns or stops. The were aligned in northwest-to-southeast direction.