Experts believe the fossil is nearly 70 million years old and likely came from an herbivorous species of dinosaur

The Denver Museum of Nature & Science already houses a vast trove of dinosaur bones, but it recently received an unexpected addition to the collection. The latest fossil didn’t come from a generous benefactor or anonymous donor–it came from beneath the museum’s own parking lot.

The partial vertebra appeared inside a 2.5-inch-diameter column of rock that researchers drilled, earning the title of the oldest and deepest dinosaur fossil found in Denver