Knowing what's behind the walls, as well as what goes into them, can be quite the illuminating experience. Rick invites architecture professor Kathryn Rogers Merlino from the University of Washington to help make sense of flying buttresses and Roman ruins. And for something exotic, we'll also get a snapshot of what it's like to visit Katmandu, and read our latest round of listeners' travel haiku. For more information on Travel with Rick Steves - including episode descriptions, program archives and related details - visit www.ricksteves.com.