A large boulder used as decoration in a rural Australian high school’s foyer is actually covered in dinosaur footprints —it just took around 20 years for anyone to notice. After examining the ancient rock,

A palaeontologist’s call-out for rocks bearing dinosaur footprints around an Australian town has borne fruit, including a densely packed set of prints sitting in the foyer of the local high school, unbeknown to many students.

For two decades, students walked past an unassuming beige rock on their way to and from class—and occasionally stuck wads of used chewing gum on it. Now, paleontologists have discovered the slab is covered in 200-million-year-old dinosaur tracks,