Collard greens are growing in Milan. Collards and Clemson okra and red Tabasco chile peppers. They and dozens of distinctly American vegetables and herbs are sprouting out of the quarter-acre "vertical farm" growing along the length of the USA Pavilion at Expo Milano, the vast world's fair under way through October 31 some six miles northwest of the Piazza del Duomo as the pigeon flies. This year's theme: How to feed a rapidly growing world population. Number of countries participating: 145. Official mascots: a gaggle of smiling, anthropomorphized fruits and veggies (including Guagliò the Garlic and Rodolfo the Fig). What's cool about America's involvement at the expo? Well, there's the giant vertical farm—plus the fact that they're selling New England—style lobster rolls at the pavilion's food truck court and that volunteer "student ambassadors" are decked out in custom Brooks Brothers navy blazers and red-white-and-blue neckerchiefs. But what's really compelling, even if you can't make it to the fair, is the group's earnest mission to educate four million visitors about the scope of American cuisine, its traditions and its future. "You come here and learn about the regionality of barbecue and Thanksgiving," says Mitchell Davis, on loan from the James Beard Foundation as the pavilion's chief creative director. "But the interesting thing is the range of different voices in the exhibition: the researchers, urban farmers, chefs and everyone in between. And a lot of them disagree about the future of food and how we're going to feed everyone—but that, too, is a very American idea."