This week's dream: Exploring Rome's underground

Much of ancient Rome, of course, "remains hidden under visitors' feet," said Tony Perrottet in Smithsonian. Visit the Pantheon or the Colosseum and you'll notice that the buildings' foundations sit far below current street levels. Plenty of what surrounded them lies under 30 feet of accumulated debris and new construction. That's what makes the underground "Roman archaeology's final frontier," inspiring two groups of amateur spelunkers to begin leading subterranean tours, opening up "a fascinating...