"We're now selling to people who wouldn't venture below 57th Street a few months ago," said Helene Sohn, a vice president of the Corcoran Group, in the firm's report.

The choice signals the importance of the South as a battleground in the next contest for the White House; only rarely has the Republican Party ventured below the Mason-Dixon line for its quadrennial celebration.

But when Windows became both a mega-tourist attraction and a destination for New Yorkers who rarely ventured below 14th Street, it seemed to symbolize the change in the city's fortunes.

Mortified and overwhelmed, Ms. Coventry did not ask another question for the next three decades, and she spent years of her youth making sure nobody ventured below her belt.

Experiments using visual cliffs have shown human infants and toddlers, as well as other animals of various ages, to be reluctant in venturing onto a glass floor with a view of a few meters of apparent fall-space below it.

Reza Malin, the team's leader, had seemed almost excited by the prospect of venturing below it.

Despite this, Haleakalā is popular with tourists and locals alike, who often venture to its summit, or to the visitor center just below the summit, to view the sunrise.

So if one was prone to fits of nervousness, one was better off staying on the upper level and not venturing below ground at all.

Ms. Johnson said that when she was single in Manhattan, she rarely ventured above 14th Street; Mr. Viles conceded that he rarely ventured below it.

Harry Feinman was stocky and muscular, six inches shorter than Arthur, with premature ash-gray hair receding on all fronts but his neck, where it ventured as stiff fuzz below the collar of his black leather jacket.