Mer-men and mer-women will be out en masse on Coney Island this Saturday afternoon for the 29th annual Mermaid Parade. The boardwalk and surrounding streets will be teeming with thousands of people dressed up as mermaids, Neptunes, and sea creatures real and imagined. The parade also features antique cars, marching bands, drill teams, themed floats, and even a helium balloon. In this week's Arts File, Kerry Nolan speaks with Brooklyn borough historian Ron Schweiger about the past and present of the parade.