The Day the Floor Fell.

THE signposts of Madison Square as it appeared in the mid-'60s are fewer and fewer. The luster has been restored to the Flatiron Building. A gleaming apartment tower is climbing to the sky at Madison and 23rd Street. On the east side of Broadway, at 23rd Street, a high-rise condominium has replaced an entire blockfront of low buildings. But a vestige of that era remains affixed to the facade of the condominium on Broadway, a plaque that stands as a haunting reminder of a tragic event. [ABSTRACT FROM PUBLISHER]