New York Mayor Rudolph Giuliani has begun a second career - photographer.

His handiwork, including shots at City Hall, from a police helicopter and at a water main break, go on exhibit next month at the Leica Gallery in Greenwich Village.The gallery will show 23 of the mayor's photos from May 8 to June 13 and will sell 50 prints, all signed by the mayor, for $500. The money will go to New Yorkers for Children.