Alfred Lunt and Lynn Fontanne werre America’s greatest theatre couple. In the early 1900s the Lunts built an estate in Wisconsin as a retreat, “filling it with treasures of antiques and decorative arts, and luring such luminaries as Laurence Olivier and Noel Coward to rest here outside the spotlights’ glare. Now it has joined the ranks of Wisconsin’s historic home-museums. Upwards of 20,000 visitors a year are expected to tour the Lunts’ estate, which has been turned into a world-class center for theater history and arts.