On display in Dinosaur National Monument‘s Quarry Exhibit Hall is this outstanding specimen:
Quite a few fossils were removed from (what is now) Dinosaur National Monument back in the early 20th century — this is a cast of one particularly historic one. In particular, this is the most-complete long-necked dinosaur (sauropod) ever found.
Deposited 149 million years ago and discovered by paleontologists working for the Carnegie Museum in 1919, it allowed scientists to reconstruct a sauropod skeleton based on a single specimen for the first time. Camarasaurus was one of the most common sauropods of the Jurassic, and grew up to 50 feet (15 meters) in length.
This is a cast, by the way — the original (as with most of the fossils found in this quarry) is in the Carnegie Museum collections, and can be seen if you visit the Carnegie Museum in Pittsburgh, Pennsylvania.