The Denver Museum of Nature and Science is filled with exhibits of dinosaur skeletons. And in the scientific equivalent of tossing couch cushions, its scientists discovered a dinosaur fossil deep — really deep — below the surface of one of its own parking lots, the museum announced this week.

A museum in Denver has found a fossil that is almost 70 million years old under its parking lot while running an unrelated drilling project. "This may be the most unusual dinosaur discovery I have ever been a part of," said Patrick O’Connor, director of Earth & Space Sciences at the Denver Museum of Nature & Science, in a statement.