It's like something out of a Flannery O'Connor story. The setting is the small town of Natchez, Miss., which was built on an unstable, water-soluble bluff. An entire street, Clifton Avenue, collapsed about 20 years ago. Swallowed up. A few years back—in 1995, to be exact, Sen. Trent Lott urged Congress to shore up the bluff to save not just people—two women died in a 1980 street collapse—but "to protect these historically significant properties and to prevent potential loss of lives," as he put it.