From downtown New Orleans, if you really, really want to follow the Mississippi River all the way to its mouth at the Gulf of Mexico, you can. (Well, almost …) From the Superdome, take the US-90 bridge south across the river to Gretna, where you can join the Belle Chasse Highway (Hwy-23), which follows alongside the river for about 75 miles, ending up at Venice, still a dozen miles from the gulf, on the fringes of the Delta National Wildlife Refuge. Apart from swamps and giant freighters, the main sight along the route is old Fort Jackson, eight miles northeast of Venice. Built following the War of 1812 to help protect the river from invasion, Fort Jackson was flooded and badly damaged by the Hurricane Katrina storm surge.