AVERY ISLAND, La. -The air smells like hot sauce, and the grounds are a virtual tropical paradise. A few small alligators are out warming their tough hides, and it’s a warm day in February.

I love this place. Every now and then I hack my way through the swamp, southward through the pretty towns of St. Martinville and New Iberia, all the way to Avery Island, the largest and most useful of South Louisiana’s five salt domes.