There’s an old Levon Helm song that goes, “I was born in the rain on the Pontchartrain,” and I’ve read about the big lake north of New Orleans in many books, but this week I got to see it for myself. It is BIG, an oval about 25 miles by 30 miles or so. We found a state park on the north shore, and from the campground we could see New Orleans rising like an architectural ghost on the far shore. Much closer was the 25-mile-long causeway that bisects the lake and connects the north shore to the city; it begins in Mandeville, Louisiana, and that’s where Fontainbleau State Park is located. Lake Pontchartrain, with New Orleans in the far distance I learned a bit of marine lore and some history, too, while we were there. First, it’s called Lake Pontchartrain, but it’s actually a lagoon—it’s salt water, and it is connected to the Gulf of Mexico by a small channel. I read a fun fact, the only way you can get into the city of New Orleans without crossing a bridge is by boat . . . The stat...