Chicago's favorite dinosaur is celebrating its 25th birthday today—well, sort of. Sue, the largest and best preserved Tyrannosaurus rex ever found, was discovered in South Dakota on this day in 1990. While the actual age of the dinosaur is somewhere around 67 million years old, the anniversary is worth celebrating. Sue was close to never being discovered, and she was even closer to ending up somewhere other than The Field Museum.
While leaving a fossil dig in the Cheyenne River Indian Reservation, a group of workers from the Black Hills Institute found a flat tire on their truck. Paleontologist Sue Hendrickson stayed behind while the rest of the group went into town for repairs, and she stumbled upon the T. rex remains in a set of nearby cliffs that the group had not explored. After a lengthy legal dispute, The Field Museum purchased the skeleton in 1997 for a final cost of more than $8.3 million.
If you're an Illinois resident, you can check out the ancient beast bones for free today, as it's a Discount Day at the museum.