Now this is weird. There are dinosaur footprints at Gettysburg, the historic Civil War battlefield in Pennsylvania. What's even weirder, their footprints are on a bridge built in 1937! There's a perfectly reasonable explanation, told to us by the Adams County Historical Society at Gettysburg. This story isn't exactly a secret, but thousands of people pass that way to check out the historical site and have no idea. It's something neat you'll need to remember and check out if you go there in the future.