Saddle a two-wheeler under the magnificent shadow of the Gateway Arch specifically, at the intersection of Leonor K. Sullivan Boulevard and Biddle Street, the exact point where the locally maintained Riverfront Trail segues into the Mississippi River Trail, governed by a multistate consortium from Minnesota to Louisiana. Point the bicycle due south, and pedal. Through the gaping maw of woebegone industrial relics you'll pass, but only for a mile or two; remind yourself that everything old does ultimately turn new again, and that while this territory awaits its urban revitalization, there's a certain Langston Hughes charm about it. Eventually the trail (which is not always a trail per se; it does take to a few city streets, as noted by the maps accessible on the MRT Web site) will take you past the pocket parks of Lyon, Minniewood and Bellerive before depositing you on South Broadway. Before long you're skirting Jefferson Barracks County Park. You might contemplate seeing the trail all the way to its conclusion in New Orleans but you've got to start heading back: Your city of St. Louis still wants you.