The Glass House McDonald's spans the Turner Turnpike a few miles south of Vinita, and at 29,000 square feet it claims to be the world's largest McDonald's. Whether or not that record still stands, it is certainly one of the strangest: you eat in a glass-enclosed bridge over a four-lane divided highway, watching traffic pass below you in both directions.
It is not worth going out of your way for, but if you are driving the turnpike it's an easy stop and a genuinely odd experience. The structure dates to 1957 when it was built as an upscale highway rest facility. A photo from the parking lot captures the absurdity of the scale perfectly.