05/28/2026
In 2017, construction workers in Thornton, Colorado were digging the foundation for a new public safety building when their equipment struck something massive buried underground. What they uncovered turned out to be one of the rarest dinosaur discoveries in Colorado history.
At first, paleontologists believed the fossil belonged to a Triceratops. But after 12 days of excavation, the truth became clear. The skull belonged to a Torosaurus, a much rarer relative recognized by the enormous openings in its frill.
The team recovered nearly 80% of the skull and parts of the skeleton, making it one of the most complete Torosaurus specimens ever found in the state. The animal lived around 66 million years ago, when the Denver Basin was a lush floodplain filled with some of the last dinosaurs to walk Earth before the extinction event.
Today, the fossil is housed at the Denver Museum of Nature & Science, a reminder that entire prehistoric worlds still lie hidden beneath modern cities.
📸: City of Thornton
