Happy Birthday G.R.R! One of the most scenic roadways in the area is celebrating a milestone this week. The Great River Road, a 3,000-mile stretch of highway along the Mississippi River which winds from Minnesota to the Gulf of Mexico, is turning 75. The Mississippi River Parkway Commission is gathering Friday in downtown St. Louis to celebrate. A ceremony on the significance, economic and tourism impact of the road is planned at the riverfront stage beneath the Gateway Arch. The commission is a multi-state organization that promotes tourism along the Great River Road. Commission officials say travelers spend more than $25 billion annually in communities along the Great River Road, supporting thousands of jobs in ten states.