Considering George Vanderbilt created the 250-room château on 8,000 acres more than a century ago as a retreat for family and friends, the additions fit with the site's legacy. "We're selling the idea of escape," says Chris Cavanaugh, Biltmore's vice president of marketing. "We made a conscious decision several years ago to begin focusing upon not just the features, but also the benefits to our guests of visiting America's largest home. And the benefit that best matched up with the history of the estate, but also matched up with our guests' needs, was escape."

The strategy has worked. The Biltmore Estate doesn't release annual figures, but Cavanaugh says visitors number between 900,000 and one million. In 2002, the first full year with the new inn, attendance rose 6.5 percent over 2000, the last full year without it, at a time when attendance declined at other heritage sites nationwide.

At Conner Prairie, a 19th-century open-air living-history museum on 1,400 acres north of Indianapolis, attendance has soared, increasing 67 percent in four years since executives there began studying visitor reaction, changing its offerings, and rethinking its marketing. "People don't think of us as a museum," says Ellen Rosenthal, Conner Prairie's executive director. "We are an attraction, like Disney World is an attraction."

So they looked to theme parks for ideas. "Theme parks create a varied experience that includes rides, performances, shopping, food, comfort - being able to sit down and rest - and the aesthetics of the place," Rosenthal says. "But the primary importance from a history museum's point of view is that they've figured out how to involve the visitor in the experience."